Sept. 6, 1883] 



NA TURE 



455 



now extinct, and similar evidences exist on the Laurentian high- 

 lands on the east. 



Perhaps the most remarkable feature of the region is that 

 immense series of ridges of drift piled against an escarpment of 

 I aramie and cretaceous rocks, at an elevation of about twenty- 

 five hundred feet, and known as the "Missouri coteau. " It is 

 in some places thirty miles broad and a hundred and eighty feet 

 in height above the plain at its foot, and extends north and south 

 for a great distance ; being, in fact, the northern extension of 

 those great ridges of drift which have been traced south of the 

 Great Lakes, and through Pennsylvania and New Jersey, and 

 which figure on the ge. ilogical maps as the edge of the continental 

 glacier, — an explanation obviously inapplicable in those western 

 as w here they attain their greatest development. It is plain 

 that in the north it marks the western limit of the deep water of 

 a glacial sea, which at some periods extended much farther west, 

 perhaps with a greater proportionate depression in going west- 

 ward, and on which heavy ice from the Laurentian di-tricts on 

 the east was wafted south-westward by the Arctic currents, while 

 lighter ice from the Rocky Mountains was being borne eastward 

 from these mountains by the prevailing westerly w inds. We thus 

 have in the west, on a very wide scale, the same phenomena of 

 varying submergence, cold currents, great ice-floes, and local 

 glaciers producing icebergs, to which I have attributed the boul- 

 der clay and upper boulder drift of eastern Canada. 



A few subsidiary points I may be pardoned for mentioning 

 here. The rival theories of the glacial period are often charac- 

 terised as th se of land glaciation and sea-borne icebergs. But 

 it mu t be remembered that those who reject the idea of a conti- 

 nental glacier hold to the existence of Leal glaciers on the high 

 lands more or less extensive during different portions of the great 

 pleistocene submergence. They also believe in the extension of 

 these glaciers seawards and partly water-borne, in the manner so 

 well explained by Mattieu Williams ; in the existence of those 

 va-t floes and fields of current and tide borne ice whose powers 

 of transport and erosion we n >w know to be so great ; and in a 

 great submergence and re-elevation of the land, bringing all parts 

 of it and all elevations up to five thousand feet successively under 

 the influence of these various agencies, along with those of the 

 ocean currents. They also hold that, at the beginning of the 

 glacial submergence, the land wa< deeply covered by decomposed 

 rock, similar to that which still exists on the hills of the southern 

 states, and which, as Dr. Hunt has shown, would afford not oidy 

 earthy debris, but large quantities of boulders ready for trans- 

 portation by ice. 



I would also remark that there has been the greatest possible 

 exaggeration as to the erosive action of land ice. In 1865, after 

 a visit to the Alpine glaciers, I maintained that in these mountains 

 glaciers are rela'ively protective rather than erosive agencies, 

 and that the detritus which the glacier streams deliver is derived 

 mostly from the atm -spherically wasted peaks and cliffs that 

 pr Ject abive them. Since that time many other observers have 

 maintained like views, and very recently Mr. Davis of Cambridge 

 and Mr. A. Irving have ably treated this subject. 1 Smoothing 

 and striation of rocks are undoubtedly important effects both of 

 land glaciers and heavy sea-borne ice ; but the levelling and 

 filling agency of these is much greater than the erosive. As a 

 matter of fact, as Newberry, Hunt, Belt, Spencer, and others 

 have shown, the glacial age has dammed up vast numbers of old 

 channels which it has been left for modern streams partially to 

 excavate. 



The till, or boulder clay, has been called a " ground moraine," 

 but there are really no Alpine moraines at all corresponding to 

 it. On the other hand, it is more or less stratified, often rests on 

 soft materials « hich glaciers would have swept away, sometimes 

 contains marine shells, or passes into marine clays in its hori- 

 zontal extension, and invariably in its embedded boulders and its 

 paste shows an unoxidised condition which could not have existed 

 if it had been a sub-aerial deposit. When the Canadian till is 

 excavated and expose I to the air, it assumes a brown colour, 

 owing to oxidation of its iron; and many of its stones and 

 boulders break up and disintegrate under the action of air and 

 fi st. These are unequivocal signs of a sub-aqueous depo-it. 

 II re and there we find associated with if, and especially near 

 the bottom and at the top, indications of powerful water-action, 

 as if of laud torrents acting at particular elevations of the land, 

 or heavy surf and ice action on coasts ; and the attempts to 

 explain these by glacial streams have been far from successful. 

 A singular objection sometimes raised against the sub aqueous 

 1 Proc.Bost. Soc. Nat. Hist. xxii. Journ. Geo!. Sec. Lond., Feb., 1883. 



origin of the till is its general want of marine remains, but this 

 is by no means universal ; and it is well known that coars: 

 conglomerates of all ages are generally destitute of fossils, except 

 in their pebbles ; and it is further to be observed that the 

 conditions of an ice-laden sea are not th >se most favoura le for 

 the extension of marine life, and that the period of time civered 

 by the glacial age must have been short compared with that 

 represented by some of the older formations. 



This last consideration suggests a question which might aff jrd 

 scope for another address of an hour's duration, — the question 

 how long time has elapsed since the close of the glacial period. 

 Recently the opini >n has been gaining ground that the close of 

 the ice age is very recent. Such reasons as the following lead to 

 this conclu-ion : the amount of atmospheric decay of rocks and of 

 denudation in general, which have occurred since the close of the 

 glacial period, are scarcely appreciable; litile erosionof river-valleys 

 or of coast- terraces has occurred. The calculated recession of w ater- 

 fall sand of production of lake-ridges leads to the same conclusion. 

 So do the recent state of bones and shells in the pleistocene 

 deposits, and the perfectly modern ficies of their fossils. On 

 such evidence the cessation of the glacial cold and settlement of 

 our continents at their present levels are events which may have 

 occurred not more than six thousand or seven thousand year ago, 

 though such time estimates are proverbially uncertain in geology. 

 This subject also carries with it the greatest of all geological 

 problems, next to that of the origin of life ; namely, the origin 

 and early history of man. Such questions cannot he discussed 

 in the closing sentences of an hour's address. I shall only draw 

 from them one practical inference. Since the comparatively 

 short post-glacial and recent periods apparently include the whole 

 of human history, we are but new comers on the earth, and 

 therefore have had little opportunity to solve the great problems 

 which it presents to us. But this is not all. tie -logy as a 

 science scarcely dates from a century ago. We have reason for 

 surprise in these circumstances that it has learned so much, but 

 for equal surprise that so many persons appear to think it a 

 complete and full-grown science, and that it is entitled to speak 

 with confidence on all the great mysteries of the earth that have 

 been hidden from the generations before us. Such being the 

 newness of man and of his science of the earth, it is not ton 

 much to say that humility, hard work in collecting facts, and 

 abstinence from hasty geh mid characterise 



geologists, at least for a few generations to come. 



In conclusion, science is light, and light is good ; but it must 

 be carried high, else it will fail to enlighten the world. Let us 

 strive to raise it high enough to shine over every obstruction 

 which casts any shad iw on the true interests of humanity. 

 Above all, let us hold up the light, and not stand in it our elves. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Dr. Matthew Hay, assistant to the Professor of Materia 

 Medica in the University of Edinburgh, has been appointed to 

 the Chair of Medical Logic and Medical Jurisprudence in the 

 University of Aberdeen, vice Prof. Ogston resigned. 



The constitution of the College for North Wales, which is to 

 be established at Bangor, having been approved by the Educa- 

 tion Department, arrangements are actively progressing for its 

 opening in January, in order to secure the annual grant of 4C00/. 

 which has been offered by Government. As in South Wales, 

 temporary premises will be acquired, and possibly the Masonic 

 Hall, a commodious building lately erected by Major Piatt, will 

 be so utilised. Nothing definite is yet arranged as t > the site of 

 the College ; but it is under-tood that Lord Pent hyn, who has 

 evinced a very active interest in the movement, and to whom will 

 probably be offered the honour of being first president, will afford 

 every facility to the executive committee. About 30,000/. has 

 been promised in subscriptions towards the building fund. 



SCIENTIFIC SERIALS 



fournal of the Russian Chemical and Physical Society, vol. XV, 

 fasc. 6. — On the action of haloidhydric acids upon oxymethylene, 

 by B. Tischenko. — On the constitution of the waters that 

 accompany naphtha and are ejected by mud volcanoes, by A. 

 Potilitzin. — On the formation of bromides of aromatic hydro- 

 carbons by the action of bromine and bromide of aluminium 

 on the volatile parts of naphtha, by G. Gustavson. — On the 



