CHAPTER IX

GRAVEYARDS

"The crust of our globe," writes a distinguished scientist, "is a great cemetery, where the rocks are tombstones on which the buried dead have written their own epitaphs." The reading of these epitaphs is the business of geology; and too often, as we shall see, the record is that of a violent and sudden death.

With the doctrine of Uniformity as a theoretical proposition, I shall have little to say. At best it is a pure assumption that the present quiet and regular action of the elements has always prevailed in the past, or that this supposition is sufficient to explain the facts of the rocks. In its more extreme form it becomes an iron dogma, which shuts out all evidence not agreeable to its teachings. But in its essential nature, whether in its least or its most extreme form, it is not approaching the subject from the right standpoint. It seeks to show how the past geological changes may have occurred; it never attempts to prove how they =must= have occurred. And I may say in passing, that it is largely for the purpose of avoiding the cumulative character of the evidence gathered from every stone quarry and from every section of strata in every corner of the globe, that the uniformitarians have wished to have these burials take place on the installment plan; for otherwise the violent and catastrophic character of the events recorded in the rocks would become too plainly manifest. But if a coroner, called upon to hold an inquest, were to content himself, after the manner of Lyell and Hutton, with glittering generalities about how people are all the time dying of old age, fever, or other causes, coupled with assurances of the quiet, regular habits and good reputation of all his fellow citizens, I do not think that he would be praised for his adherence to inductive methods if we could get at clear and decisive evidence that the poor fellow under examination had been shot. Just so with common-sense methods in geology. =A true induction is capable of finding out for certain= whether or not the present quiet regular action of the elements has always prevailed in the past; and it is most unscientific to assume, as the followers of Hutton and Lyell have done, that the comparatively insignificant changes within historic time have always prevailed in the past, when there is plenty of clear and decisive evidence to the contrary.

The general fact which I wish to develop in this chapter may be stated somewhat as follows:

=Rocks belonging to all the various systems or formations give us fossils in such a state of preservation, and heaped together in such astonishing numbers, that we cannot resist the conviction that the majority of these deposits were formed in some sudden and not modern manner, catastrophic in nature.=

But before giving any examples of these abnormal deposits we must first study the modern normal deposits; before we can rightly understand the sharp contrast between the ancient and the modern action of the elements, we must become familiar with the way in which fossils are now being buried by our rivers and oceans.

One of the many geological myths dissipated by the work of the "Challenger" Expedition, which, as Zittel says, "marks the grandest scientific event of the nineteenth century," is that about the ocean bottom and the work now being carried on there. The older text-books taught that, not only was the bottom of the ocean thickly strewn with the remains of the animals which died there and in the waters above, but also that the oceanic currents were constantly wearing away in some places and building up in others over all the ocean floor, and hence producing true stratified deposits. Accordingly it was said that it was only necessary for these beds to be lifted above the surface to produce the ordinary rocks that we find everywhere about us. But we now know that the ocean currents have, as Dana says, "no sensible, mechanical effects, either in the way of transportation or abrasion."[55] We know also that all kinds of sediment drop so much quicker in salt water than in fresh, that none of it gets beyond the narrow "continental shelf" and the classic 100 fathom line, which in most cases is not very far from shore. In the north Atlantic there are sediments found in deeper water produced by ice-floes or icebergs dropping their loads there; but we cannot suppose such work to have gone on when the Arctic regions were clothed with a temperate-climate vegetation, much less that such things occurred over all the earth. On the floor of the open ocean, and away from the tracks of our modern icebergs, we have two or three kinds of mud or ooze formed from minute particles of organic matter; but besides these =absolutely nothing= save a possible sprinkling of volcanic products, which of course are limited in their distribution. Where then can we find a stratified or bedded structure now being formed over the ocean bottom? Dana says there is nothing of the kind now being produced there, save as the result of possible variations during the passing ages in the organic deposits thrown down, where a bed of ooze may be supposed to be thrown down directly upon another kind of ooze. There is =no gravel=, =no sand=, =no clay=, but whatever variation there might be in the organic deposits, the new kind would be laid down immediately upon the preceding similar deposits, unless a thin sprinkling of volcanic dust happened to intervene.

Thus to explain practically all the deposits found in the rocks, we are absolutely limited to the shore deposits and the mouths of large rivers. Here we certainly have alternations of sand, clay and gravel, producing a true bedded structure. But I ask: What kind of organic remains will we get from these modern deposits? Certainly nothing like the crowded graveyards which we find everywhere in the ancient ones.

Darwin, in his famous chapter on "The Imperfection of the Geological Record," has well shown how scanty and imperfect are the modern fossiliferous deposits. The progress of research has only confirmed and accentuated the argument there presented on this point. Thus Nordenskiold, the veteran Arctic explorer, remarks with amazement on the scarcity of recent organic remains in the Arctic regions, where such a profusion of animal life exists; while in spite of the great numbers of cats, dogs and other domestic animals which are constantly being thrown into rivers like the Hudson or the Thames, dredgings about their mouths have revealed the surprising fact that scarcely a trace of any of them is there to be found.[56]

Even the fishes themselves stand a very poor chance of being buried intact. As Dana[57] puts it:

"Vertebrate animals, as fishes, reptiles, etc., which fall to pieces when the animal portion is removed, =require speedy burial after death=, to escape destruction from this source (decomposition and chemical solution from air, rain-water, etc.), as well as from animals that would prey upon them."

If a vertebrate fish should die a natural death, which of itself must be a rare occurrence, the carcass would soon be devoured whole or bit by bit by other creatures near by. Possibly the lower jaw, or the teeth, spines, etc., in the case of sharks, or a bone or two of the skeleton, might be buried unbroken, but a whole vertebrate fish entombed in a modern deposit is surely a unique occurrence.

But every geologist knows that the remains of fishes are, in countless millions of cases, found in a marvelous state of preservation. They have been entombed in =whole shoals=, with the beds containing them miles in extent, and scattered over all the globe. Indeed, so accustomed have we grown to this state of affairs in the rocks we hammer up, that if we fail to find such well-preserved remains of vertebrate fishes, land animals, or plants, we feel disappointed, almost hurt; we think that nature has somehow slighted this particular set of beds. But where in our modern quiet earth will we go to find deposits now forming like the copper slate of the Mansfield district, the Jurassic shales of Solenhofen, the calcareous marls of Oeningen on Lake Constance, the black slates of Glarus, or the shales of Monte Bolca?--to mention some cases from the Continent of Europe more than usually famous in the literature for exquisitely preserved vertebrate fishes, to say nothing of other fossils. According to Dana, all these must have met with a "speedy burial after death"--perhaps before, who knows?

Buckland[58] in speaking of the fossil fish of Monte Bolca, which may be taken as typical of all the others, is quite positive that these fish must have "perished suddenly," by some tremendous catastrophe.

"The skeletons of these fish," he says, "lie parallel to the laminae of the strata of the calcareous slate; they are always entire, and so closely packed on one another that many individuals are often contained in a single block.... =All these fish must have died suddenly= on this fatal spot, and have been speedily buried in the calcareous sediment then in course of deposition. From the fact that certain individuals have even preserved traces of color upon their skin, we are certain that they were entombed before decomposition of their soft parts had taken place."

In many places in America as well as Europe, where these remains of fish are found, the shaley rock is so full of fish oil that it will burn almost like coal, while some have even thought that the peculiar deposits like Albertite "coal" and some cannel coals were formed from the distillation of the fish oil from the supersaturated rocks.

De La Beche[59] was also of the opinion that most of the fossils were buried suddenly and in an abnormal manner. "A very large proportion of them," he says, "must have been =entombed uninjured, and many alive=, or, if not alive, at least before decomposition ensued." In this he is speaking not of the fishes alone but of the fossiliferous deposits in general.

There is a series of strata found in all parts of the world which used to be called the "Old Red Sandstone," now known as the Devonian. In this, almost wherever we find it, the remains of whole shoals of fishes occur in such profusion and preservation that the "period" is often known as the "Age of Fishes." Dr. David Page, after enumerating nearly a dozen genera, says:

"These fishes seem to have thronged the waters of the period, and their remains are often found in masses, =as if they had been suddenly entombed in living shoals= by the sediment which now contains them."

I beg leave to quote somewhat at length the picturesque language of Hugh Miller[60] regarding these rocks as found in Scotland.

"The river bull-head, when attacked by an enemy, or immediately as it feels the hook in its jaws, erects its two spines at nearly right angles with the plates of the head, as if to render itself as difficult of being swallowed as possible. The attitude is one of danger and alarm; and it is a curious fact, to which I shall afterward have occasion to advert, that =in this attitude nine-tenths of the= _Pterichthes_ =of the Lower Old Red Sandstone are to be found=.... It presents us, too, with a wonderful record of violent death falling at once, not on a few individuals, but on whole tribes."

"At this period of our history, some terrible catastrophe involved in sudden destruction the fish of an area at least a hundred miles from boundary to boundary, perhaps much more. The same platform in Orkney as at Cromarty is strewed thick with remains, which exhibit unequivocally the marks of violent death. The figures are contorted, contracted, curved, the tail in many instances is bent round to the head; the spines stick out; the fins are spread to the full, as in fish that die in convulsions.... The record is one of destruction at once widely spread and total, so far as it extended.... By what quiet but potent agency of destruction were the innumerable existences of =an area perhaps ten thousand square miles in extent annihilated at once=, and yet the medium in which they had lived left undisturbed in its operations?

"Conjecture lacks footing in grappling with the enigma, and expatiates in uncertainty over all the known phenomena of death."

I shall not taunt the uniformitarians by asking them to direct us to some modern analogies. But I would have the reader remember that these Devonian and other rocks are absolutely world-wide in extent.

Surely Howorth is talking good science when he says that his masters Sedgwick and Murchison taught him "that no plainer witness is to be found of any physical fact than that Nature has at times worked with enormous energy and rapidity," and "that the rocky strata teem with evidence of violent and sudden dislocations on a great scale."

I have spoken only of the class Fishes. But what other class of the animal kingdom will not point us a similar lesson? The Reptiles and Amphibians, to say nothing of the larger Mammals, are also found in countless myriads, packed together as if in natural graveyards. Everybody knows of the enormous numbers and splendid preservation of the great reptiles of the Western and Southern States, untombed by Leidy, Cope and Marsh. One patch of Cretaceous strata in England, the Wealden, has afforded over thirty different species of dinosaurs, crocodiles, and pleisosaurs. Mr. Chas. H. Sternberg, one of Zittel's assistants, recently reported great quantities of Amphibians from the Permian of Texas. They are of all sizes, some frogs being six feet long, others ten. Besides these he found three "bone-beds" full of minute forms an inch or less in length. Of the small ones, which I judge must represent whole millions of young ones =suddenly= entombed, he says:

"I got over twenty perfect skulls, many with vertebrae attached, and thousands of small bones from all parts of the skeleton. In one case, a complete skull, one-fourth of an inch in length, had connected with it nearly the entire vertebral column, with ribs in position, coiled upon itself, bedded with many bones of other species in a red silicious matrix. So perfectly were they weathered out that they lay in bas-relief =as white and perfect as if they had died a month ago=; a single row of teeth, =like the points of cambric needles=, occupied both sets of jaws."[61]

How many more such cases there may have been in these "three bone-beds full" of similar remains, it would be interesting to know. But though somewhat aside from the present subject, I cannot refrain in passing from referring to the wonderful preservation of these remains. It is preposterous to say that these bones have lain thus exposed to the weather for the millions of years postulated by the popular theory. There is not a particle of scientific evidence to prove that they are not just as recent as any specimen from the Tertiaries or the Pleistocene. Buffon and Cuvier proved the mammals to be of "recent" age, because they occurred in the superficial deposits. They never heard of the Triassic, Jurassic, and Cretaceous of Colorado and Wyoming, nor these Permian of Texas. Think of this frog's teeth "like the points of cambric needles," and he and his fellows "as perfect as if they had died a month ago." Of one of the big six-foot specimens this author says: "Its head was so beautifully preserved, and cleaned under long erosion, it was difficult to believe it was not a recent specimen." While of the little six-inch fellow referred to above he says: "The bones of the skull are perfectly preserved, quite smooth, and show the sutures distinctly; there is no distortion, some red matrix attached below seems absolutely necessary to convince the mind that it is not =a thing of yesterday=." James Geikie[62] mentions the case of the Elgin sandstones "formerly classed as 'Old Red,'" but which are now called Triassic, "from the fact that they have yielded reptilian remains of a higher grade than one would expect to meet with in old Red Sandstone." Since these strata =slide up and down so easily=, we have here far more urgent scientific reasons for calling these amphibian remains of Texas among the most "recent" geological deposits on the globe.

But I must return to my subject. The Invertebrates are also eloquent to the fact of abnormal conditions having prevailed when their remains were entombed. We could go through the whole list, but it is the same old story of abnormal deposits, essentially different from anything that is being made to-day.

Where, for instance, in the modern seas, will we find the remains of polyp-corals now being intercalated between beds of clays or sands over vast areas, as we find them in the Lias and Oolyte of England and elsewhere? Corals require a definite depth of water, neither too deep nor too shallow, but it must be clear and pure; and nothing but some awful catastrophe could place a bed of coral remains a few feet or a =few inches= in thickness over the vast areas that we find them. Crinoids require the same clear, pure water, but much deeper, some of the modern kinds living =over a mile down=, but every student of the science knows that the Subcarboniferous limestone of both Europe and America (called Mountain Limestone in England), so noted for its crinoids and its corals, is constantly found intercalated between shale or sandstone, or between the coal beds themselves as at Springfield, Ill., or in the Lower Coal Measures of Westmorland County, Pa. There are of course, here and there, great masses of these rocks which represent an original formation by growth _in situ_; but no sane man can say this for these great sheets perhaps =only a few inches= in thickness, for in many cases they show a stratified or bedded structure just as much as a sandstone or a shale. In some tables given by Dana on pp. 651-2 of his "Manual," compiled from four different localities, I count no less than =23 beds= of limestone thus intercalated, though we are not told how many of them contain corals or crinoids. Such details are generally omitted as of little consequence.

Next, let us try the Lamellibranchs, such as the clam, oyster, and other true bivalves. These creatures have an arrangement in the hinge region by which the valves of the shell tend to open, but during life are held together by the adductor muscles. When dead, however, these muscles relax and decay, and then the valves spread wide open. Of course there are some, such as certain kinds of clams, which burrow in the mud or sand, and the shells of these, if they happened to die a natural death in their holes, could not spread very far apart. However =some mud= must even then wash into their burrows and into their empty shells. But many kinds of bivalves do not thus burrow in the ground; and when the fossils of such kinds are found in quantity with the valves =applied= and often =hollow=, as is so frequently the case in many of the "older" rocks, I cannot see how we are to understand any ordinary conditions of deposit. And yet we are gravely assured by a high authority, that "A sudden burial is not necessary to entombment in this condition."

Or, let us take the Brachiopods. These have a bivalve shell, the parts of which, however, are not pulled apart after death, and only need to open a little way even in life to admit the sea water which brings them their food. Yet, though the valves do not gape after death, there is when dead and empty a =hole= at the hinge or beak, which would readily admit mud if such were present in the water, or if the shells after death were subject to the ordinary movements of tide, wave and current. Yet Dawson[63] says of the Brachiopods, Spirifer and Athyris:

"I may mention here that in all the Carboniferous limestones of Nova Scotia the shells of this family are usually found with the valves closed and =the interior often hollow=."

Of course he tries to explain how this state of things might occur "in deep and clear water"--for some of the modern species are found in the clear depths 18,000 feet down--and he thinks that their entombment in this condition "does not prove that the death of the animals was sudden." But we now know that there is no means of producing a stratified formation in this "deep and clear water," and hence that some revolution of nature is implied by the conditions in which we find them.

Some people seem to have converted David Hume's famous sentence into a scientific formula, thus: "Anything contrary to Uniformity is impossible: hence no amount of evidence can prove anything contrary to Uniformity."

For the trouble in this case is that, not only do such conditions prevail "in all the Carboniferous limestones of Nova Scotia," which must be several thousands of square miles in extent, but in the Devonian shales and Silurian limestones of Ontario and the Middle States at least--perhaps over the rest of the world--the Brachiopods are found =in this same tell-tale condition=, and it would establish a very dangerous precedent to admit abnormal conditions in even a single case.

I have only touched upon the voluminous evidence that might be adduced in the case of the lower forms of life. Had I the space, I might show how the marvelously preserved plants of the coal beds tell the same story. But we must pass on to consider the remains of the larger land animals. I have already given a quotation from Dana about the mammoth and rhinoceros in Northern Siberia, where he says that their encasing in ice and the perfect preservation of their flesh "shows that the cold finally became =suddenly= extreme, as of a single winter's night, and knew no relenting afterward." Not very many serious attempts have been made to account for this remarkable state of things, which is a protest against uniformity that can be appreciated by a child, and I never heard of any theory which attempted to account for the facts without some kind of awful catastrophe.

Many, however, seem to have little idea of the extent of these remains in the Arctic regions. They are not all thus perfectly preserved, for thousands of skeletons are found in localities where the ground thaws out somewhat in the short summer, and here of course, the skin and tissues could not remain intact. Remains of these beasts occur in only a little less abundance over all Western Europe, and the mammoth also in North America, well preserved specimens having been obtained from the Klondike region of Alaska; and there is nothing to forbid the idea that many, if not most of these latter specimens were also at one time enshrined as "mummies" in the ice, which has since melted over the more temperate regions. But we must confine ourselves to the remains in Siberia. Flower and Lydekker tell us that since the tenth century at least, these remains have been quarried for the sake of the ivory tusks, and a regular trade in this fossil ivory, in a state fit for commercial purposes, has been carried on "both eastward to China, and westward to Europe," and that "fossil ivory has its price current as well as wheat."

"They are found at all suitable places along the whole line of the shore between the mouth of the Obi and Behring Straits, and the further north the more numerous do they become, the islands of New Siberia being now one of the favorite collecting localities. The soil of Bear Island and of Liachoff Islands is said to consist only of sand and ice with such quantities of mammoth bones as almost to compose its chief substance. The remains are not only found around the mouths of the great rivers, as would be the case if the carcasses had been washed down from more southern localities in the interior of the continent, but are imbedded in the frozen soil in such circumstances as to indicate that the animals had lived not far from the localities in which they are now found, and they are exposed either by the melting of the ice in unusually warm summers, or by the washing away of the sea cliffs or river banks by storms or floods. In this way the bodies of more or less nearly perfect animals, even standing in the erect position, with the soft parts and hairy covering entire, have been brought to light."[64]

But these remains of the mammoth, though the best known, are not the only ones attesting extraordinary conditions: though of course in warmer latitudes we do not find perfect "mummies" with the hide and flesh preserved untainted. Let us go to a warmer climate, to Sicily, and read a description of the remains of the hippopotamus found there. I quote from Sir Joseph Prestwich:

"The chief localities, which centre on the hills around Palermo, arrest attention from the extraordinary quantity of bones of _Hippopotami_ (in complete hecatombs) which have there been found. Twenty tons of these bones were shipped from around the one cave of San Ciro, near Palermo, within the first six months of exploiting them, and they were so fresh that they were sent to Marseilles to furnish animal charcoal for use in the sugar factories. How could this bone breccia have been accumulated?... The only suggestion that has been made is that the bones are those of successive generations of _Hippopotami_ which went there to die. But this is not the habit of the animal, and besides, the bones are those of animals =of all ages down to the foetus=, nor do they show traces of weathering or exposure....

"My supposition is, therefore, that when the island was submerged, the animate in the plain of Palermo naturally retreated, as the waters advanced, deeper into the amphitheatre of hills until they found themselves embayed, as in a seine, with promontories running out to sea on either side and a mural precipice in front. As the area became more and more circumscribed the animals must have thronged together in vast multitudes, crushing into the more accessible caves, and swarming over the ground at their entrance, until overtaken by the waters and destroyed."[65]

Our author then adds this summary of his argument:

"The extremely fresh condition of the bones, proved by the retention of so large a proportion of animal matter, and the fact that animals of all ages were involved in the catastrophe, shows that the event was geologically, comparatively recent, as other facts show it to have been sudden."

That it must have been a good deal more "sudden" than even this author will admit, is evident from the nature of the hippopotamus. I never thought that it was particularly afraid of the water, or likely to be drowned by any such moderate catastrophe as Prestwich invokes in this singular volume. The reader must, however, note that this affair, like the entombment of the mammoth, certainly =took place since man was upon the globe=, even according to the uniformitarians. Would it not be economy of energy to correlate the two together? But if man dates from "Miocene times," as some contend, he must have witnessed half a dozen awful affairs like these, for there is scarcely a country on the globe that has not been under the ocean since then.

Let us proceed.

But whither shall we turn to avoid finding similar phenomena? The vast deposits of mammals in the Rocky Mountains may occur to the reader. As Dana says, they "have been found to be literally Tertiary burial grounds." I need not go into the details of these deposits, nor of those in other places containing the great mammals which must have been contemporary with "Tertiary man," for I would only weary the reader with a monotony of abnormal conditions of deposit--unlike anything now being produced this wide world over. We shall be stating the case very mildly indeed, if we conclude that the vast majority of the fossils, by their profuse abundance and their astonishing preservation, tell a very plain story of "speedy burial after death," and =are of an essentially different character= from modern deposits.

Prof. Nicholson, in speaking of the remains of the Zeuglodon, says:

"Remains of these gigantic whales are very common in the 'Jackson beds' of the Southern United States. So common are they that, according to Dana, 'the large vertebrae, some of them a foot and a half long and a foot in diameter, were formerly so abundant over the country in Alabama that they were used for making walls, or were burned to rid the fields of them.'"[66]

Shortly before his death in 1895, Dana prepared a revised edition of his "Manual," and in it he gives us quite a rational explanation of this case, as follows:

"Vertebrae were so abundant, on the first discovery, in some places that many of these Eocene whales must have been stranded together in a common catastrophe, on the northern borders of the Mexican Gulf--possibly by a series of earthquake waves of great violence; or by an elevation along the sea limit that made a confined basin of the border region, which the hot sun rendered destructive alike to Zeuglodons and their game; or by an unusual retreat of the tide, which left them dry and floundering under a tropical sun." (p. 908.)

That is, this veteran geologist in his old age would not attempt to account for such abnormal conditions without a catastrophe of some kind. But if we use similar explanations for similar conditions, where shall we stop through the whole range of the rocks from the Cambrian to the Pleistocene?

Dana became very fond of this idea of earthquake waves, and invoked them to account for "the universality and abruptness" with which the species disappear at the close of "Palaeozoic time," using as the generating cause the uplifting of the Appalachian Mountains, with "flexures miles in height and space, and slips along newly opened fractures that kept up their interrupted progress through thousands of feet of displacement," from which he says "incalculable violence and great surgings of the ocean should have occurred and been often repeated.... Under such circumstances the devastation of the sea border and the low-lying lands of the period, the destruction of their animals and plants, would have been a sure result. The survivors within a long distance of the coast line would have been few."[67]

But as this sudden break in the life-chain "was so general and extensive that no Carboniferous species is known to occur among the fossils of succeeding beds, not only in America and Europe, but also over the rest of the world" (p. 735), he is obliged to make his catastrophe by earthquake waves positively =world wide=. Hence he adds: "The same waves would have swept over European land and seas, and there found coadjutors for new strife in earthquake waves of European origin."

At the close of the Mesozoic he uses similar language, though in this case he has the whole range of the mountains on the west of both North and South America, the Rockies and the Andes, in length a "third of the circumference of the globe," "undergoing simultaneous orogenic movements, with like grand results." (p. 875.) "The deluging waves sent careering over the land" would, he thinks, "have been destructive over all the coasts of a hemisphere," and "may have made their marches inland for hundreds of miles" (p. 878), sweeping all before them.

I should think so; but then what becomes of this doctrine of uniformity? Personally, I have not the slightest objection to these "deluging waves sent careering over the land," for I feel sure that just such things have occurred, and on just such a scale as our author pictures, for, as he says, the destruction of species "was great, =world-wide=, and one of the most marvelous events in geological history." (p. 877.)

But it seems to me that here we have an enormous amount of energy going to waste. Others have demanded a continent to explain the appearance of a beetle in a certain locality; but here we have a great world-wide catastrophe to explain the sudden disappearance of merely a few species. Why not utilize this surplus energy in doing other necessary work, that has certainly been accomplished somehow, but has hitherto gone a-begging for a competent cause? The only thing I object to in Dana's view of the case is his way of having these "exterminations" take place on the installment plan. For in that way we have to work up a great world catastrophe to do only a very limited amount of work, and then have to repeat the thing another time for a similarly limited work, =when one such cosmic convulsion is competent to do the whole thing=. I plead for the "law of parsimony," and the economizing of energy.

The vast shoals of carcasses which seem to be piled up in almost every corner of the world are _prima facie_ evidence that our old globe has witnessed some sort of cosmic convulsion. The exact cause, nature, and extent of this event we may never have sufficient facts to determine, though two or three additional facts having a bearing on the subject will be considered in the following chapters.

FOOTNOTES:

[55] "Manual," p. 229.

[56] _Pop. Sci. Mo._, Vol. xxi, pp. 143, 693.

[57] "Manual," p. 141.

[58] "Geol. and Min.," Vol. I., pp. 124-5. Ed. 1858.

[59] "Theoretical Geol.," p. 265. London, 1834.

[60] "Old Red Sandstone," pp. 48, 221-2.

[61] _Pop. Sci. News_, May, 1902, pp. 106-7.

[62] "Histor. Geol.," p. 53.

[63] "Acadian Geol.," p. 260.

[64] "Mammals," p. 430.

[65] "On Certain Phenomena, etc.," pp. 50-52.

[66] "Ancient Life-History," p. 300.

[67] "Manual," p. 736.