50^ 



NATURE [September 20. 1894 



As ihe powers of geology matured it became increasingly able 

 to dispense with catastrophes. The very diluvium itself was 

 shown to be local in its distribution, and glacial in its origin : 

 masses of moving ice, like that which buries the greater part of 

 Greenland out of sight, covered a large part of the temperate 

 regions, and this it was that produced the curious scratched 

 stonci and the deposits containing them, which are consequently 

 no longer called "diluvial" but "glacial." More important yet, 

 land could be shown to be still actually rising from the sea, and 

 mountains growing into the air, but so slowly that the fact was 

 not established without much dispute, which is haidly yet over. 

 Valleys could be shown to result, not from any bodily fracturing 

 of the land, but from the slow wearing action of the rivers 

 which flow through them, and the waves of the sea wete shown 

 to be capable of cutting down cliffs and of reducing Ihe land to 

 a plain. 



From these facts the discordance in the succession of stratified 

 rocks found an easy solution. Recurring to the instance of the 

 carboniferous rocks and their relations to the trias, we no longer 

 need suppose that the stupendous force which folded the car- 

 boniferous rocks and raised them into the air, acted suddenly or 

 even very rapidly ; judging from the rate at which mountains rise 

 now, their upheaval may have proceeded slowly ; a few feet in 

 a century would suflice. If we allow but one foot in a century, 

 i' would only require two millions of years to produce a moun- 

 tain range 20,000 feet in height. The movement might naturally 

 be expected to be accompanied by earlhqu.ikes, but there is 

 nothing to lead us to suppose that these would be on a much 

 grander scale than those of the present. During its slow ele- 

 vation, the mountain range would be exposed to wind and 

 weather, rain and rivers would carve it out into ridges and 

 valleys, and frost would splinter its peaks into spires and 

 pinnacles. Subsequently it would sink benealh the sea, and 

 the waves of the «ea, as they battered down its cliff-, would 

 remove the last remnants which had escaped the rain and rivers, 

 and toll over an unbroken plain. On this plain, as it continued 

 slowly to subside beneath the sen, the immense deposits of the 

 trias. Has, lower oolites, and Oxford clay would be piled up. 



If the rise of the sea-floor into the Uristol Alps look place 

 slowly, and involved a great lapse of time, so equally did the 

 sinking of the land to form the sea-floor afresh, and in this long 

 interval time was afforded for great changes in the organic 

 wo'ld ; and thus we reach an explanation of the great and 

 striking differences which distinguish the fossils of the carbon- 

 iferous rocks from lho.se of later date. 



There is no insuperable diffically In this explanation ; its 

 great merit lies in Its accordance with the course of nature as we 

 observe It at the present day ; and henceforward it became the 

 motto of geology that the processes of the present furnish llickcy 

 to the Interpretation of the past. The changes In which the life of 

 the earth Is manliest are not only slow ar.d gradual now, but 

 they have ever been the same. The earthquakes, which in 

 nncicnt times shook the land, were no more violent than those 

 oi which we have lately read in the daily new.spapcrs ; the ancient 

 volcanoes were not more terrible in their outbursts than 

 Krakatoa ; floods were not more appalling than lhu>c which 

 still from lime lo time sweep away tens or even hundreds of 

 ibou-^andf of human beings from the Ganges I'lain, and the 

 earth, instead of falling into convulsions every now and then, 

 proceeds on the even ttnour of her way, without haste and with- 

 out rest, preserving a uniformity in herpro^'ress which Impresses 

 ui with Its solemn grandeur, but which sometimes seems 

 a trifle monotonous. From Its belief that an unbroken 

 uniformity in the operations of nature extends from the present 

 into the most remote past, geology now came lo be called 

 "uniformllarlan." It was no lunger theologic, no longer 

 catastrophic, and, I am sorry to add, no longer cosmologic. 

 It perslilcntly refused to inquire Into the early history of our 

 planet, and rcstticling Its .-tudy to the accessible parts of ihc 

 carlh's crust, it abdicated its regal position as the science of the 

 earth, and became as il were a mete petty chieftain, dealing only 

 with rocks and the fossils Ihcy conlain ; the fossils, by the way, 

 not righlly belonging to its province at all. And It wa-. because 

 it pasted from being a science of the earth to become a mere 

 tludy of rocks and lossili, that Ilullon was able to make his 

 famous declaration ihat as a te ull of his inquiries into the 

 system of nature he could discover "no vestige of a beginning, 

 no prospect of an end." Apart from ihl.', however, and in its 

 self-llmilcd career, geology pursued a luminous advance, and 

 as il did so the Noachian deluge began to sink into an oblivion 



which it might be thought to have scarcely merited. For If 

 the biblical account Is to be taken literally, it furnishes us with a 

 catastrophe of the first order, and since it is said to have occurred 

 comparatively recently, orat least in historic time, iheuniformi- 

 tirian, by his own principles, would have been compelled to 

 infer, as the catastrophist luid done, that such deluges form a 

 p.irt of the orderly scheme of the world. The univeisality of 

 the deluge had, however, for various reasons, been denied, not 

 only by geologists, but by writers of other schools of thought, 

 and towards the middle of the century, belief in il amojigst 

 the learned was gr.idually expiring ; such a number and variety 

 of convincing arguments as converged a;;ainst it could indeed 

 but lead to that result ; and that the deluge, so far from helug 

 universal, was a local, and very local phenomenon, became an 

 article of belief, so settled amongst all good geologists — and I 

 think I may add iheologists — that It may be said to have tinally 

 fallen into the deep slumber of a decided opinion, from which I 

 for one have no desire looroufe it. 



Thus the deluge, so far from shaking the uniformitariau 



position, was rather itself submerged by unifoiniilarian views, 



and growing geology was In danger of taking the uniformitariau 



formula for an infallible dogma. It was saved from this by 



physics, a clever brother of its own, which had now discovered 



the famous principle of the "conservation of energy," and 



another equally famous, "thedlsslpalion of energy." I'romthese 



it was deduclble that the duration of the earth as a living planet 



must be strictly limited In time. It must have hail a beginning, 



I and at the beginning w.is furnished with a store ol energv, 



] which it has ever since been spending. In this spending of 



1 energy its life consii:s, and when the store is at length ex- 



j hausted its life will cease, audit will become numbered amongst 



j the dead planets. 



A good deal of this uniformltarian geology might perhaps 

 Itself have guessed, had It extended iis views beyond rocks ami 

 fossils to the stars and other shining bodies which people the 

 vast realms of space. The present then, strange to say, will 

 still afford a key to the past. We have but to turn to the sun, 

 our nearest luminary, though slill more than ninety millions of 

 miles away from us, and in that great orb we find much lo sug- 

 gest the sLiieof our planet souie ninety millions of years ago or 

 more. It is scarcely necessary to remind )ou of the fact that 

 the sun is a body so hot that the most refractory substances 

 known to us on the earili exist In it in a state of gas or vapour ; 

 tongues of glowing gas shoot from it like flames; the clouds 

 which emit lis biilliaiii light are probably clouds of carbon or 

 silicon, which have momentarily condensed from a g.iseou* 

 slate ; and rain, if rain ever occur-, must be a rain of molten 

 metals, such as iron, which will be disaipaied In gas before it has 

 fallen very far. 



If we i)roceed to the more remo'.e nebula;, largely composed 

 of glowing masses of gas, we find a suggestion of a sMge more 

 embryonic still, when iiie earth had as yet no separate existence, 

 but formed, with us sister planets and the sun, a single shining 

 cloud. On the other hand. If we lurn our ga/.e on our nearest 

 relative — offspring possibly — ihai dead planet, Ihe moon, «c 

 may read in its pallid disc ihe sad reminder, "Such as I am, 

 you, too, some day will be." 



liut this was not all that was contained In the admonilion of 

 physics ; it showed not only that the earth is mortal, but that 

 its span of life, as measured in years, or millions of years, is 

 brief compared to the almost unliniiied periods which geology 

 had been in the habii of pustulating. If caiastrophic geology 

 had at limes pushed nature to almost indecent extremes I'l 

 haste, unilormiiarian geology, on the other haml, had erred in 

 the opposite direction, aii.l pictured naluie when she was 

 "young and wantoned in her prime," as moving with the tame 

 sedateness of advanced middle age. It became necessary, 

 therefore, as Dr. Ilaughlun expresses it, "to hurry up the 

 phenomena." 



With Its uniformitarianism thus moderated, geology has again 

 become cosmologic, and neglecting no study lh.it can throw 

 light on any question connecicd with our planet, h.rs regained 

 its position as the science of the earth : it is henceforth known 

 as ivolutlonal geology. 



The change has not taken place without occasional relaps:s 

 Into catastrophism. .Some Indications of this can, 1 fancy, be 

 perceived In the wriiings ul that eiiiinenlly great geologist 

 .Sucss, who, amongst other suggestions savouring ol heresy, 

 has lately recalled altention 10 Ihc " Deluge," and cndeavourtil 

 lo show thai though ceitainly local, and indeed confined lo ihe 



NO. 1299, VOL. 50] 



