SOME UNDISCOVERED TRUTHS IN GEOLOGY.

Waikato Times, Volume XXI, Issue 1772, 13 November 1883, Page 3

SOME UNDISCOVERED TRUTHS IN GEOLOGY.

At a recent mooting of the American Association foi the Advancement of Sucnc, lichltilMontic.il, thu president, DvJ. W. Daw son, dclneiod a most interesting lectuio on this sul)jeet, honi which we make tlie following extracts :—: — In hiu-li i>, wide sweep we need not be suipiiscd to le.un that theic ,uc yet some unsolved problems. We aie met at the outset with an enquiry tu> to man's place in thoNatuic he lias to study. Hisoict.misin ib ccitainly :i part of Nature, and he is the tci initial link of a long chain of being. As, i scientific animal, man finds within himself . i mind more potent than matter and th it leacts on Nat mo. Wciecognise this dillieulty w hen w e divide science into experimental and observational. It doe-s little pood to meet mysteries by guesses, nor should we on the other hand lesign oin selves to ignoiaiKe. We must wie&tlo with the unsolved questions of Nature, masteiing wh.it we can, and leaving other* to be grappled with by our successors. In piocccdmg to mark out the limits of asm taming knowledge, the speaker began with the oldest locks, a formation ot immense thickness, and coi-rc-ponding to what used to be called fundamental gi.rnite. Ht, intimated his behet that tin- \. as dispoMted as gneiss horn a shoreless ocean. The Lower Liurentian looks piohably limit our jiiogics-. backward, beyond which 'ie only physical hypotheses a« to a cooling incandescent globe. Ascending, we met with significant changes. Beds ot limestone aie associated with the buds of gneiss, Gravel beds show the existence of shores ; and giaphite infoi ms us of .some soib of plant life, and iion oicsof oiganicmattei. In the Middle Laiwcutian appcired the Eoznmi C ui'Di'l' >isr, probably the oldest £01 111 of life ot which we have any knowledge. Mctamoi phiMn ne\t came into play. Nothing m geology perishes Heat 111.13 change clays into .slales, and limestones into marbles : but nothing wholly disappear. Agient battle iageso\oi the genealogy of the rocks, the .steps of which Dr Dawson setfoith, claiminv that the sudden incoming of life in a .11 ied foims b.illled biologists and iurniJied an unsolved problem. The theoiß-s ot evolution aie lir-ufhoiont to account ioi it. The pioees-, still is as mysteiious as ever, and a gnat gap is lei fc 111 oiu accumulated knowledge. Suppose that w(> stai t, however, with a iHimboi ot oigiiuism.i leady made ; we ,\<-k, how can these have \;n ied <-o as to givt us new species? It is a singular iillusion that vaiiatiou may l)e bouudleso, aimless, and foituitous, and that development aliios iioiu spout uicous selection. Y.uieties must, have cause, and the vast and oiderly succession of Natiuc must be legulited by fixed laws, only a few of which are known to us. One consideration showing how impel feet aie our attempts fo icacli the true causes of geiicia and ppeiics, is the icinarkablo fixity of lea ling types. Tiace certain foims ot life along their own line tlnough stupendous vicissitudes and across the ages, and you find them substantially unchanged. ] ( ] vain pies aie the foliage and fructification of mosses, the venation of wings of insects, the fetructuie and iorm of .snails, all of which were settled in the caibomferous age. Huxley holds that there are but two possible alternatives as to the 01 iqin of species, vi/ , 1. Mechanical construction, '2. Evolution. But we know that instead of two there aio mimeious possible methods, such as absolute creation, mediate ci cation, critical evolution, and giadual evolution. The origin of whales a Holds an example of the difliculties ausuig from lefernng existing forms to imaguidiy ancestois. (laudiy, though a stiong evolutionist, candidly says, "We have questioned these stiauge and gigantic soverigns of the tertiary oceans, and they leave us without a reply." The periods ot lapul introductions of new foims of life were nob penods of struggle for existence, but of expension ; while the real peiiods of stiugglo were marked by depaupeiisation and existence. Another unsolved problem is the inability of paleontology to fill gaps in the chain of being. Many lines ot bang present a continuous chain. On the other hand, the aluupt and simultaneous appear ance of new types in many specific and generic forms, over wide areas, obliges evolutionists to assume periods of exceptional activity alternating with stagnation — a doetiine seaicely diflering fiom the old theory of special creation. Plainly a vast amount of conscientious work is needed to account for those breaks in the chain. Another mystery yet unexplained is the cause of the great movements ot the eai th's crust by which mountains and plains and ocean beds have been formed. It is known, however, that much is due to the unequal settling of the earth towards it centre, and also to the pressure of the ocean agaiust the shore. Complex movements of plication are more easily _ comprehended than the regular pulsations of flat continental areas, each change being accompanied by changes of climate, plants, and animals. The problems as to coal formations, the ancient fncoids on algte and the ureat and much debated glacial period next received attention. What caused the great climatic changes that have occurred during geological time? How came there to be a vast continental glacier reaching as far south as the 40th degree of latitude and thousands of feet thick ? Shall we not aftei all have to give up this favourite theory ? May not many of the phenomena be explained by supposing a glacial sea with Artie currents and icebergs wafted southward are due to local glaciers ? It may also be questioned if glaciers are not relatively protective rather than erosive agencies, and if sufficient importance has been attached to their work in levelling and filling up hills and channels. Still another que&tiou is as to how long a time has elapsed sinpe the glacial era. Recently the qpinion has been gaining ground that its cessation dates back only 6000 or 7000 years. This problem, of course carries with it the question of the origin and early history of man. The practical inference is that we are but newcomers on this earth, and have had but little time to 'solve such great problems. Geology is young— scarcely a a century old. We are surprised that so many regard it as a complete, and $vU|

grown science. Humility, hard work, and abstinence from hasty generalisations should characterise geologists for at least a few geneiations to come. Science is light, and light is good. Let us raise it high enough to shine over every obstruction that casts any shadow on the true interests of humamity. Above all, let us hold up the light and not stand in it ourselves.