But although the animals of the early geological deposits indicate shallow seas by their similarity to our shoal-water animals, it must not be supposed that they are by any means the same. On the contrary, the old shells, crustacea, corals, etc., represent types which have existed in all times with the same essential structural elements, but under different specific forms in the several geological periods. And here it may not be amiss to say something of what are called by naturalists representative types.
The statement that different sets of animals and plants have characterized the successive epochs is often understood as indicating a difference of another kind than that which distinguishes animals now living in different parts of the world. This is a mistake. There are so-called representative types all over the globe, united to each other by structural relations and separated by specific differences of the same kind as those that unite and separate animals of different geological periods. Take, for instance, mud-flats or sandy shores in the same latitudes of Europe and America; we find living on each, animals of the same structural character and of the same general appearance, but with certain specific differences, as of color, size, external appendages, etc. They represent each other on the two continents. The American wolves, foxes, bears, rabbits, are not the same as the European, but those of one continent are as true to their respective types as those of the other; under a somewhat different aspect they represent the same groups of animals. In certain latitudes, or under conditions of nearer proximity, these differences may be less marked. It is well known that there is a great monotony of type, not only among animals and plants, but in the human races also, throughout the Arctic regions; and some animals characteristic of the high North reappear under such identical forms in the neighborhood of the snow-fields in lofty mountains, that to trace the difference between the ptarmigans, rabbits, and other gnawing animals of the Alps, for instance, and those of the Arctics, is among the most difficult problems of modern science.
And so it is also with the animated world of past ages; in similar deposits of sand, mud, or lime, in adjoining regions of the same geological age, identical remains of animals and plants may be found; while at greater distances, but under similar circumstances, representative species may occur. In very remote regions, however, whether the circumstances be similar or dissimilar, the general aspect of the organic world differs greatly, remoteness in space being thus in some measure an indication of the degree of affinity between different faunæ. In deposits of different geological periods immediately following each other, we sometimes find remains of animals and plants so closely allied to those of earlier or later periods that at first sight the specific differences are hardly discernible. The difficulty of solving these questions, and of appreciating correctly the differences and similarities between such closely allied organisms, explains the antagonistic views of many naturalists respecting the range of existence of animals, during longer or shorter geological periods; and the superficial way in which discussions concerning the transition of species are carried on, is mainly owing to an ignorance of the conditions above alluded to. My own personal observation and experience in these matters have led me to the conviction that every geological period has had its own representatives, and that no single species has been repeated in successive ages.
The laws regulating the geographical distribution of animals, and their combination into distinct zoölogical provinces called faunæ, with definite limits, are very imperfectly understood as yet; but so closely are all things linked together from the beginning that I am convinced we shall never find the clew to their meaning till we carry on our investigations in the past and the present simultaneously. The same principle according to which animal and vegetable life is distributed over the surface of the earth now, prevailed in the earliest geological periods. The geological deposits of all times have had their characteristic faunæ under various zones, their zoölogical provinces presenting special combinations of animal and vegetable life over certain regions, and their representative types reproducing in different countries, but under similar latitudes, the same groups with specific differences.
Of course, the nearer we approach the beginning of organic life, the less marked do we find the differences to be, and for a very obvious reason. The inequalities of the earth's surface, her mountain-barriers protecting whole continents from the Arctic winds, her open plains exposing others to the full force of the polar blasts, her snug valleys and her lofty heights, her tablelands and rolling prairies, her river-systems and her dry deserts, her cold ocean-currents pouring down from the high North on some of her shores, while warm ones from tropical seas carry their softer influence to others,—in short, all the contrasts in the external configuration of the globe, with the physical conditions attendant upon them, are naturally accompanied by a corresponding variety in animal and vegetable life.
But in the Silurian age, when there were no elevations higher than the Canadian hills, when water covered the face of the earth, with the exception of a few isolated portions lifted above the almost universal ocean, how monotonous must have been the conditions of life! And what should we expect to find on those first shores? If we are walking on a sea-beach to-day, we do not look for animals that haunt the forests or roam over the open plains, or for those that live in sheltered valleys or in inland regions or on mountain-heights. We look for Shells, for Mussels and Barnacles, for Crabs, for Shrimps, for Marine Worms, for Star-Fishes and Sea-Urchins, and we may find here and there a fish stranded on the sand or tangled in the seaweed.
The geologist cannot find his way back in the record of the great stone book, to the far-off day when life began. The various changes that come over rocks from the action of heat, of water, and of pressure, have slowly modified these ancient beds, so that they no longer preserve the frames of the animals that were buried in them.
These old rocks, which are so changed that we cannot any longer make sure that any animals lived in them, are called the "archæan," which is Greek for ancient. They were probably mud and sand and limestone when first made, but they have been changed to mica schists, gneiss, granite, marble, and other crystalline rocks. When any rock becomes crystalline, the fossils dissolve and disappear, as coins lose their stamp and form when they are melted in the jeweller's gold-pot.
These ancient rocks that lie deepest in the earth are very thick, and must have taken a great time in building; great continents must have been worn down by rain and waves in order to supply the waste out of which they were made. It is tolerably certain that they took as much time during their making as has been required for all the other times since they were formed. During the vast ages of this archæan the life of our earth began to be. We first find many certain evidences of life in the rocks which lie on top of the archæan rock, and are known as the Cambriani and Silurian periods. There we have creatures akin to our corals and crabs and worms, and others that are the distant kindred of the cuttle-fishes and of our lamp-shells. There were no backboned animals, that is to say, no land mammals, reptiles, or fishes at this stage of the earth's history. It is not likely that there was any land life except of plants and those forms like the lowest ferns, and probably mosses. Nor is it likely that there were any large continents as at the present time, but rather a host of islands lying where the great lands now are, the budding tops of the continents just appearing above the sea.
Although the life of this time was far simpler than at the present day, it had about as great variety as we would find on our present sea-floors. There were as many different species living at the same time on a given surface.
The Cambrian and Silurian time—the time before the coming of the fishes—must have endured for many million years without any great change in the world. Hosts of species lived and died; half a dozen times or more the life of the earth was greatly changed. New species came much like those that had gone before, and only a little gain here and there was perceptible at any time. Still, at the end of the Silurian, the life of the world had climbed some steps higher in structure and in intelligence.
The next set of periods is known as the Devonian. It is marked by the rapid extension of the fishes; for, although the fishes began in the uppermost Silurian, they first became abundant in this time. These, the first strong-jawed tyrants of the sea, came all at once, like a rush of the old Norman pirates into the peaceful seas of Great Britain. They made a lively time among the sluggish beings of that olden sea. Creatures that were able to meet feebler enemies were swept away or compelled to undergo great changes, and all the life of the oceans seems to have a spur given to it by these quicker-formed and quicker-willed animals. In this Devonian section of our rocks we have proofs that the lands were extensively covered with forests of low fern trees, and we find the first trace of air-breathing animals in certain insects akin to our dragon-flies. In this stage of the earth's history the fishes grew constantly more plentiful, and the seas had a great abundance of corals and crinoids. Except for the fishes, there were no very great changes in the character of the life from that which existed in the earlier time of the Cambrian and Silurian. The animals are constantly changing, but the general nature of the life remains the same as in the earlier time.
In the Carboniferous or coal-bearing age, we have the second great change in the character of the life on the earth. Of the earlier times, we have preserved only the rocks formed in the seas. But rarely do we find any trace of the land life or even of the life that lived along the shores. In this Carboniferous time, however, we have very extensive sheets of rocks which were formed in swamps in the way shown in the earlier part of this book. They constitute our coal-beds, which, though much worn away by rain and sea, still cover a large part of the land surface. These beds of coal grew in the air, and, although the swamps where they were formed had very little animal life in them, we find some fossils which tell us that the life of the land was making great progress; there are new insects, including beetles, cockroaches, spiders, and scorpions, and, what is far more important, there are some air-breathing, back-boned animals, akin to the salamanders and water-dogs of the present day. These were nearly as large as alligators, and of much the same shape, but they were probably born from the egg in the shape of tadpoles and lived for a time in the water as our young frogs, toads, and salamanders do. This is the first step upwards from the fishes to land vertebrates; and we may well be interested in it, for it makes one most important advance in creatures through whose lives our own existence became possible. Still, these ancient woods of the coal period must have had little of the life we now associate with the forests; there were still no birds, no serpents, no true lizards, no suck-giving animals, no flowers, and no fruits. These coal-period forests were sombre wastes of shade, with no sound save those of the wind, the thunder, and the volcano, or of the running streams and the waves on the shores.
In the seas of the Carboniferous time, we notice that the ancient life of the earth is passing away. Many creatures, such as the trilobites, die out, and many other forms such as the crinoids or sea lilies become fewer in kind and of less importance. These marks of decay in the marine life continue into the beds just after the Carboniferous, known as the Permian, which are really the last stages of the coal-bearing period.
When with the changing time we pass to the beds known as the Triassic, which were made just after the close of the Carboniferous time, we find the earth undergoing swift changes in its life. The moist climate and low lands that caused the swamps to grow so rapidly have ceased to be, and in their place we appear to have warm, dry air, and higher lands.
On these lands of the Triassic time the air-breathing life made very rapid advances. The plants are seen to undergo considerable changes. The ferns no longer make up all the forests, but trees more like the pines began to abound, and insects became more plentiful and more varied.
FIG. 3. CYCAS CIRCINALIS, AKIN TO HIGHEST PLANTS OF COAL TIME.
Hitherto the only land back-boned animal was akin to our salamanders. Now we have true lizards in abundance, many of them of large size. Some of them were probably plant-eaters, but most were flesh-eaters; some seem to have been tenants of the early swamps, and some dwelt in the forests.
The creatures related to the salamanders have increased in the variety of their forms to a wonderful extent. We know them best by the tracks which they have left on the mud stones formed on the borders of lakes or the edge of the sea. In some places these footprints are found in amazing numbers and perfection. The best place for them is in the Connecticut Valley, near Turner's Falls, Mass. At this point the red sandstone and shale beds, which are composed of thin layers having a total thickness of several hundred feet, are often stamped over by these footprints like the mud of a barnyard. From the little we can determine from these footprints, the creatures seem to have been somewhat related to our frogs, but they generally had tails, and, though provided with four legs, were in the habit of walking on the hind ones alone like the kangaroo. A few of these tracks are shown in the figure on this page.
These strange creatures were of many different species. Some of them must have been six or seven feet high, for their steps are as much as three feet apart, and seem to imply a creature weighing several hundred pounds. Others were not bigger than robins. Strangely enough, we have never found their bones nor the creatures on which they fed, and but for the formation of a little patch of rocks here and there we should not have had even these footprints to prove to us that such creatures had lived in the Connecticut Valley in this far-off time.
FIG. 5. FOOT-PRINT, TURNER'S FALLS.
But these wonderful forms are less interesting than two or three little fossil jaw-bones that prove to us that in this Triassic time the earth now bore another animal more akin to ourselves, in the shape of a little creature that gave suck to its young. Once more life takes a long upward step in this little opossum-like animal, perhaps the first creature whose young was born alive. These little creatures called Microlestes or Dromatherium, of which only one or two different but related species have been found in England and in North Carolina, appear to have been insect-eaters of about the size and shape of the Australian creature shown in Fig. 7. So far we know it in but few specimens,—altogether only an ounce or two of bones,—but they are very precious monuments of the past.
In this Triassic time the climate appears to have been rather dry, for in it we have many extensive deposits of salt formed by the evaporation of closed lakes, of seas, such as are now forming on the bottom of the Dead Sea, and the Great Salt Lake of Utah, and a hundred or more other similar basins of the present day.
In the sea animals of this time we find many changes. Already some of the giant lizard-like animals, which first took shape on the land, are becoming swimming-animals. They changed their feet to paddles, which, with the help of a flattened tail, force them through the water.
The fishes on which these great swimming lizards preyed are more like the fishes of our present day than they were before. The trilobites are gone, and of the crinoids only a remnant is left. Most of the corals of the earlier days have disappeared, but the mollusks have not changed more than they did at several different times in the earliest stages of the earth's history.
After the Trias comes a long succession of ages in which the life of the world is steadily advancing to higher and higher planes; but for a long time there is no such startling change as that which came in the passage from the coal series of rocks to the Trias. This long set of periods is known to geologists as the age of reptiles. It is well named, for the kindred of the lizards then had the control of the land. There were then none of our large fish to dispute their control, so they shaped themselves to suit all the occupations that could give them a chance for a living. Some remained beasts of prey like our alligators, but grew to larger size; some took to eating the plants, and came to walk on their four legs as our ordinary beasts do, no longer dragging themselves on their bellies as do the lizard and alligator, their lower kindred. Others became flying creatures like our bats, only vastly larger, often with a spread of wing of fifteen or twenty feet. Yet others, even as strangely shaped, dwelt with the sharks in the sea.
In this time of the earth's history we have the first bird-like forms. They were feathered creatures, with bills carrying true teeth, and with strong wings; but they were reptiles in many features, having long, pointed tails such as none of our existing birds have. They show us that the birds are the descendants of reptiles, coming off from them as a branch does from the parent tree. The tortoises began in this series of rocks. At first they are marine or swimming forms, the box-turtles coming later. Here too begin many of the higher insects. Creatures like moths and bees appear, and the forests are enlivened with all the important kinds of insects, though the species were very different from those now living.
In the age of reptiles the plants have made a considerable advance. Palms are plenty; forms akin to our pines and firs abound, and the old flowerless group of ferns begins to shrink in size, and no longer spreads its feathery foliage over all the land as before. Still there were none of our common broad-leaved trees; the world had not yet known the oaks, birches, maples, or any of our hard-wood trees that lose their leaves in autumn; nor were the flowering plants, those with gay blossoms, yet on the earth. The woods and fields were doubtless fresh and green, but they wanted the grace of blossoms, plants, and singing-birds. None of the animals could have had the social qualities or the finer instincts that are so common among animals of the present day. There were probably no social animals like our ants and bees, no merry singing creatures; probably no forms that went in herds. Life was a dull round of uncared-for birth, cruel self-seeking, and of death. The animals at best were clumsy, poorly-endowed creatures, with hardly more intelligence than our alligators.
The little thread of higher life begun in the Microlestes and Dromatherium, the little insect-eating mammals of the forest, is visible all through this time. It held in its warm blood the powers of the time to come, but it was an insignificant thing among the mighty cold-blooded reptiles of these ancient lands. There are several species of them, but they are all small, and have no chance to make headway against the older masters of the earth.
The Jurassic or first part of the reptilian time shades insensibly into the second part, called the Cretaceous, which immediately follows it. During this period the lands were undergoing perpetual changes; rather deep seas came to cover much of the land surfaces, and there is some reason to believe that the climate of the earth became much colder than it had been, at least in those regions where the great reptiles had flourished. It may be that it is due to a colder climate that we owe the rapid passing away of this gigantic reptilian life of the previous age. The reptiles, being cold-blooded, cannot stand even a moderate winter cold, save when they are so small that they can crawl deep into crevices in the rocks to sleep the winter away, guarded from the cold by the warmth of the earth. At any rate these gigantic animals rapidly ceased to be, so that by the middle of the Cretaceous period they were almost all gone, except those that inhabited the sea; and at the end of this time they had shrunk to lizards in size. The birds continue to increase and to become more like those of our day; their tails shrink away, their long bills lose their teeth; they are mostly water-birds of large size, and there are none of our songsters yet; still they are for the first time perfect birds, and no longer half-lizard in their nature.
The greatest change in the plants is found in the coming of the broad-leaved trees belonging to the families of our oaks, maples, etc. Now for the first time our woods take on their aspect of to-day; pines and other cone-bearers mingle with the more varied foliage of nut-bearing or large-seeded trees. Curiously enough, we lose sight of the little mammals of the earlier time. This is probably because there is very little in the way of land animals of this period preserved to us. There are hardly any mines or quarries in the beds of this age to bring these fossils to light. In the most of the other rocks there is more to tempt man to explore them for coal ores or building stones.
In passing from the Cretaceous to the Tertiary, we enter upon the threshold of our modern world. We leave behind all the great wonders of the old world, the gigantic reptiles, the forests of tree ferns, the seas full of ammonites and belemnites, and come among the no less wonderful but more familiar modern forms. We come at once into lands and seas where the back-boned animals are the ruling beings. The reptiles have shrunk to a few low forms,—the small lizards, the crocodiles and alligators, the tortoises and turtles, and, as if to mark more clearly the banishment of this group from their old empire, the serpents, which are peculiarly degraded forms of reptiles which have lost the legs they once had, came to be the commonest reptiles of the earth.
The first mammals that have no pouches now appear. In earlier times, the suck-giving animals all belonged to the group that contains our opossums, kangaroos, etc. These creatures are much lower and feebler than the mammals that have no pouches. Although they have probably been on the earth two or three times as long as the higher mammals, they have never attained any eminent success whatever; they cannot endure cold climates; none of them are fitted for swimming as are the seals and whales, or for flying as the bats, or for burrowing as the moles; they are dull, weak things, which are not able to contend with their stronger, better-organized, higher kindred. They seem not only weak, but unable to fit themselves to many different kinds of existence.
In the lower part of the Tertiary rocks, we find at once a great variety of large beasts that gave suck to their young. It is likely that these creatures had come into existence in a somewhat earlier time in other lands, where we have not been able to study the fossils; for to make their wonderful forms slowly, as we believe them to have been made, would require a very long time. It is probable that during the Cretaceous time, in some land where we have not yet had a chance to study the rocks, these creatures grew to their varied forms, and that in the beginning of the Tertiary time, they spread into the regions where we find their bones.
Beginning with the Tertiary time, we find these lower kinsmen of man, through whom man came to be. The mammals were marked by much greater simplicity and likeness to each other than they now have. There were probably no monkeys, no horses, no bulls, no sheep, no goats, no seals, no whales, and no bats. All these animals had many-fingered feet. There were no cloven feet like those of our bulls, and no solid feet as our horses have. Their brains, which by their size give us a general idea of the intelligence of the creature, are small; hence we conclude that these early mammals were less intelligent than those of our day.
It would require volumes to trace the history of the growth of these early mammals, and show how they, step by step, came to their present higher state. We will take only one of the simplest of these changes, which happens to be also the one which we know best. This is the change that led to the making of our common horses, which seem to have been brought into life on the continent of North America. The most singular thing about our horses is that the feet have but one large toe or finger, the hoof, the hard covering of which is the nail of that extremity. Now it seems hard to turn the weak, five-fingered feet of the animals of the lower Tertiary—feet which seem to be better fitted for tree-climbing than anything else—into feet such as we find in the horse. Yet the change is brought about by easy stages that lead the successive creatures from the weak and loose-jointed foot of the ancient forms to the solid, single-fingered horse's hoof, which is wonderfully well-fitted for carrying a large beast at a swift speed, and is so strong a weapon of defence that an active donkey can kill a lion with a well-delivered kick.
The oldest of these creatures that lead to the horses is called Eohippus or beginning horse. This fellow had on the forefeet four large toes, each with a small hoof and fifth imperfect one, which answered to the thumb. The hind feet had gone further in the change, for they each had but three toes, each with hoofs, the middle-toed hoof larger and longer than the others. A little later toward our day we find another advance in the Orohippus, when the little imperfect thumb has disappeared, and there are only four toes on the forefeet and three on the hind.
Yet later we have the Mesohippus or half-way horse. There are still three toes on the hind foot, but one more of the fingers of the forefeet has disappeared. This time it is the little finger that goes, leaving only a small bone to show that its going was by a slow shrinking. The creature now has three little hoofs on each of its feet.
Still nearer our own time comes the Miohippus, which shows the two side hoofs on each foot shrinking up so that they do not touch the ground, but they still bear little hoofs. Lastly, about the time of man's coming on the earth, appears his faithful servant, the horse, in which those little side hoofs have disappeared, leaving only two little "splint" bones to mark the place where these side hoofs belong. Thus, step by step, our horses' feet were built up; while these parts were changing, the other parts of the animals were also slowly altering. They were at first smaller than our horses,—some of them not as large as an ordinary Newfoundland dog; others as small as foxes.
As if to remind us of his old shape, our horses now and then, but rarely, have, in place of the little splint bones above the hoof, two smaller hoofs, just like the foot of Miohippus. Sometimes these are about the size of a silver dollar, on the part that receives the shoe when horses are shod.
In this way, by slow-made changes, the early mammals pass into the higher. Out of one original part are made limbs as different as the feet of the horse, the wing of a bat, the paddle of a whale, and the hand of man. So with all the parts of the body the forms change to meet the different uses to which they are put.
At the end of this long promise, which was written in the very first animals, comes man himself, in form closely akin to the lower animals, but in mind immeasurably apart from them. We can find every part of man's body in a little different shape in the monkeys, but his mind is of a very different quality. While his lower kindred cannot be made to advance in intelligence any more than man himself can grow a horse's foot or a bat's wing, he is constantly going higher and higher in his mental and moral growth.
So far we have found but few traces of man that lead us to suppose that he has been for a long geological time on the earth, yet there is good evidence that he has been here for a hundred thousand years or more. It seems pretty clear that he has changed little in his body in all these thousands of generations. The earliest remains show us a large-brained creature, who used tools and probably had already made a servant of fire, which so admirably aids him in his work.
Besides the development of this wonderful series of animals, that we may call in a certain way our kindred, there have been several other remarkable advances in this Tertiary time, this age of crowning wonders in the earth's history. The birds have gone forward very rapidly; it is likely that there were no songsters at the first part of this period, but these singing birds have developed very rapidly in later times. Among the insects the most remarkable growth is among the ants, the bees, and their kindred. These creatures have very wonderful habits; they combine together for the making of what we may call states, they care for their young, they wage great battles, they keep slaves, they domesticate other insects, and in many ways their acts resemble the doings of man. Coming at about the same time as man, these intellectual insects help to mark this later stage of the earth as the intellectual period in its history. Now for the first time creatures are on the earth which can form societies and help each other in the difficult work of living.
Among the mollusks, the most important change is in the creation of the great, strong swimming squids, the most remarkable creatures of the sea. Some of these have arms that can stretch for fifty feet from tip to tip.
Among the plants, the most important change has been in the growth of flowering plants, which have been constantly becoming more plenty, and the plants which bear fruits have also become more numerous. The broad-leaved trees seem to be constantly gaining on the forests of narrow-leaved cone-bearers, which had in an earlier day replaced the forests of ferns.
In these Tertiary ages, as in the preceding times of the earth, the lands and seas were much changed in their shape. It seems that in the earlier ages the land had been mostly in the shape of large islands grouped close together where the continents now are. In this time, these islands grew together to form the united lands of Europe, Asia, Africa, Australia, and the twin American continents; so that, as life rose higher, the earth was better fitted for it. Still there were great troubles that it had to undergo. There were at least two different times during the Tertiary age termed glacial periods, times when the ice covered a large part of the northern continents, compelling life of all sorts to abandon great regions, and to find new places in more southern lands. Many kinds of animals and plants seem to have been destroyed in these journeys; but these times of trial, by removing the weaker and less competent creatures, made room for new forms to rise in their places. All advance in nature makes death necessary, and this must come to races as well as to individuals if the life of the world is to go onward and upward.
Looking back into the darkened past, of which we yet know but little compared with what we would like to know, we can see the great armies of living beings led onward from victory to victory toward the higher life of our own time. Each age sees some advance, though death overtakes all its creatures. Those that escape their actual enemies or accident, fall a prey to old age: volcanoes, earthquakes, glacial periods, and a host of other violent accidents sweep away the life of wide regions, yet the host moves on under a control that lies beyond the knowledge of science. Man finds himself here as the crowning victory of this long war. For him all this life appears to have striven. In his hands lies the profit of all its toil and pain. Surely this should make us feel that our duty to all these living things, that have shared in the struggle that has given man his elevation, is great, but above all, great is our duty to the powers that have been placed in our bodies and our minds.
The Pitch Lake, like most other things, owes its appearance on the surface to no convulsion or vagary at all, but to a most slow, orderly, and respectable process of nature, by which buried vegetable matter, which would have become peat, and finally brown coal, in a temperate climate, becomes, under the hot tropic soil, asphalt and oil, continually oozing up beneath the pressure of the strata above it . . . .
As we neared the shore, we perceived that the beach was black with pitch; and the breeze being off the land, the asphalt smell (not unpleasant) came off to welcome us. We rowed in, and saw in front of a little row of wooden houses a tall mulatto, in blue policeman's dress, gesticulating and shouting to us. He was the ward policeman, and I found him (as I did all the colored police) able and courteous, shrewd and trusty. These police are excellent specimens of what can be made of the negro, or half-negro, if he be but first drilled, and then given a responsibility which calls out his self-respect. He was warning our crew not to run aground on one or other of the pitch reefs, which here take the place of rocks. A large one, a hundred yards off on the left, has been almost all dug away, and carried to New York or to Paris to make asphalt-pavement.
The boat was run ashore, under his directions, on a spit of sand between the pitch; and when she ceased bumping up and down in the muddy surf, we scrambled out into a world exactly the hue of its inhabitants of every shade, from jet black to copper-brown. The pebbles on the shore were pitch. A tide-pool close by was enclosed in pitch; a four-eyes was swimming about in it, staring up at us; and when we hunted him, tried to escape, not by diving, but by jumping on shore on the pitch, and scrambling off between our legs. While the policeman, after profoundest courtesies, was gone to get a mule-cart to take us up to the lake, and planks to bridge its water channels, we took a look round at this oddest of corners of the earth.
In front of us was the unit of civilization,—the police-station, wooden, on wooden stilts (as all well-built houses are here), to insure a draught of air beneath them. We were, of course, asked to come in and sit down, but preferred looking about, under our umbrellas; for the heat was intense. The soil is half pitch, half brown earth, among which the pitch sweals in and out as tallow sweals from a candle. It is always in slow motion under the heat of the tropic sun; and no wonder if some of the cottages have sunk right and left in such a treacherous foundation. A stone or brick house could not stand here; but wood and palm-thatch are both light and tough enough to be safe, let the ground give way as it will.
The soil, however, is very rich. The pitch certainly does not injure vegetation, though plants will not grow actually in it. The first plants which caught our eyes were pine-apples, for which La Brea is famous. The heat of the soil, as well as the air, brings them to special perfection. They grow about anywhere, unprotected by hedge or fence; for the negroes here seem honest enough, at least toward each other; and at the corner of the house was a bush worth looking at, for we had heard of it for many a year. It bore prickly, heart-shaped pods an inch long, filled with seeds coated with a red waxy pulp.
This was a famous plant—Bixa orellana Roucou; and that pulp was the well-known annotto dye of commerce. In England and Holland it is used merely, I believe, to color cheeses, but in the Spanish Main to color human beings. The Indian of the Orinoco prefers paint to clothes; and when he has "roucoued" himself from head to foot, considers himself in full dress, whether for war or dancing. Doubtless he knows his own business best from long experience. Indeed, as we stood broiling on the shore, we began somewhat to regret that European manners and customs prevented our adopting the Guaraon and Arrawak fashion.
The mule-cart arrived; the lady of the party was put into it on a chair, and slowly bumped and rattled past the corner of Dundonald Street—so named after the old sea-hero, who was, in his life-time, full of projects for utilizing this same pitch—and up in pitch road, with a pitch gutter on each side.
The pitch in the road has been, most of it, laid down by hand, and is slowly working down the slight incline, leaving pools and ruts full of water, often invisible, because covered with a film of brown pitch-dust, and so letting in the unwary walker over his shoes. The pitch in the gutter-bank is in its native place, and as it spues slowly out of the soil into the ditch in odd wreaths and lumps, we could watch, in little, the process which has produced the whole deposit—probably the whole lake itself.
A bullock-cart, laden with pitch, came jolting down past us, and we observed that the lumps, when the fracture is fresh, have all a drawn out look; that the very air bubbles in them, which are often very numerous, are all drawn out likewise, long and oval, like the air-bubbles in some ductile lavas.
On our left, as we went on, the bush was low, all of yellow cassia and white Hibiscus, and tangled with lovely convolvulus-like creepers, Ipomoea and Echites, with white, purple or yellow flowers. On the right were negro huts and gardens, fewer and fewer as we went on,—all rich with fruit trees, especially with oranges, hung with fruit of every hue; and beneath them, of course, the pine-apples of La Brea. Everywhere along the road grew, seemingly wild here, that pretty low tree, Cashew, with rounded yellow-veined leaves and little green flowers, followed by a quaint pink and red-striped pear, from which hangs, at the larger and lower end, a kidney-shaped bean, which bold folk eat when roasted; but woe to those who try it when raw; for the acrid oil blisters the lips, and even while the beans are roasting the fumes of the oil will blister the cook's face if she holds it too near the fire.
As we went onward up the gentle slope (the rise is one hundred and thirty-eight feet in rather more than a mile), the ground became more and more full of pitch, and the vegetation poorer and more rushy, till it resembled, on the whole, that of an English fen. An Ipomoea or two, and a scarlet flowered dwarf Heliconia, kept up the tropic type, as does a stiff brittle fern about two feet high. We picked the weeds, which looked like English mint or basil, and found that most of them had three longitudinal nerves in each leaf, and were really Melastomas, though dwarfed into a far meaner habit than that of the noble forms we saw at Chaguanas, and again on the other side of the lake. On the right, too, in a hollow, was a whole wood of Groogroo palms, gray stemmed, gray leaved, and here and there a patch of white or black Roseau rose gracefully eight or ten feet high among the reeds.
The plateau of pitch now widened out, and the whole ground looked like an asphalt pavement, half overgrown with marsh-loving weeds, whose roots feed in the sloppy water which overlies the pitch. But, as yet, there was no sign of the lake. The incline, though gentle, shuts off the view of what is beyond. This last lip of the lake has surely overflowed, and is overflowing still, though very slowly. Its furrows all curve downward; and it is, in fact, as one of our party said, "a black glacier." The pitch, expanding under the burning sun of day, must needs expand most toward the line of least resistance—that is, downhill; and when it contracts again under the coolness of night, it contracts, surely, from the same cause, more downhill than uphill; and so each particle never returns to the spot whence it started, but rather drags the particles above it downward toward itself. At least, so it seemed to us. Thus may be explained the common mistake which is noticed by Messrs. Wall and Sawkins in their admirable description of the lake.
"All previous descriptions refer the bituminous matter scattered over the La Brea district, and especially that between the village and the lake, to streams which have issued at some former epoch from the lake, and extended into the sea. This supposition is totally incorrect, as solidification would probably have ensued before it had proceeded one-tenth of the distance; and such of the asphalt as has undoubtedly escaped from the lake has not advanced more than a few yards, and always presents the curved surfaces already described, and never appears as an extended sheet."
Agreeing with this statement as a whole, I nevertheless cannot but think it probable that a great deal of the asphalt, whether it be in large masses or in scattered veins, may be moving very slowly down hill, from the lake to the sea, by the process of expansion by day and contraction by night, and may be likened to a caterpillar, or rather caterpillars innumerable, progressing by expanding and contracting their rings, having strength enough to crawl down hill, but not strength enough to back up hill again.
At last we surmounted the last rise, and before us lay the famous lake—not at the bottom of a depression, as we expected, but at the top of a rise, whence the ground slopes away from it on two sides, and rises from it very slightly on the two others. The black pool glared and glittered in the sun. A group of islands, some twenty yards wide, were scattered about the middle of it. Beyond it rose a double forest of Moriche fan-palms; and to the right of them high wood with giant Mombins and undergrowth of Cocorite—a paradise on the other side of the Stygian pool.