TRANSACTIONS OF SECTION C. 557 



3. The interplacial beds which next succeed contain remains of a well-marked 

 temperate fauna and flora, which point to somelhinn: more than a mere partial or 

 local retreat of the inland ice. The geofjraphical distribution of the beds and the 

 presence in these of such forms as Elephas an/iqujct, C'crvus elephag, C. mer/aceros, 

 and a flora comparable to that now existing in Northern Germany, justify geologists 

 in concludinfr that the interglacial epoch was one of long duration, and characterised 

 in Germany by climatic conditions apparently not less temperate than those that 

 now obtain. One of the phases of that interglacial epoch, as we have seen, was the 

 overflowinfr of the Baltic jirovinces by the waters of the North Sea. 



4. To this well-marked interglacial epoch succeeded another epoch of arctic 

 conditions, when the Scandinavian inland ice once more invaded Germany, plough- 

 ing through the interglacial deposits, and working these up in its ground-moraine. 

 So far as 1 can learn, the prevalent belief among geologists in North Germany is 

 that there was only one interglacial epoch ; but, as already stated, doubt has been 

 expressed whether all the facts can be thus accounted for. There must always be 

 great ditticulty in the correlation of widely-separated interglacial deposit.*, and the 

 time does not seem to me to have yet come when we can definitely assert that all 

 those interglacial beds belong to one and the same geological horizon. 



I have dwelt upon the recent work of geologists in the peripheral areas of the 

 drift-covered regions of Northern Europe hecause I think the results obtained are 

 of great interest to glacialists in this country. And for the same reason I wish 

 next to call attention to what lias been done of late years in elucidating the glacial 

 geology of the Alpine lands of Central Europe — and more particularly of the low 

 grounds tiiat stretch out from the foot of the mountains. Any observations that 

 tend to throw light upon the history of the complex drifts of our own peripheral 

 areas cannot Ijut be of service. It is quite impossible to do justice in this brief 

 sketch to the labours of the many enthusiastic geologists who within recent years 

 have increased our knowledge of the glaciation of the Alpine lands. At present, 

 however, I »m not so much concerned with the proofs of general prlaciation as with 

 the evidence that goes to show how the .Alpine ground-moraines have been formed, 

 and with the facts which have led certain observers to conclude that the Alps have 

 endured several distinct glaciations within Pleistocene times. Swiss geologists are 

 agreed that the ground-moraines which clothe the bottoms of the great Alpine 

 valleys, and extend outwards sometimes for many miles upon the low grounds 

 beyond are of true glacial origin. Now these ground-moraines are closely similar 

 to the boulder-clays of this country and Northern luirope. Like them, they are 

 frequently touffh and hard-pressed, but now and again somewhat looser and less 

 firmly coherent. Frequently also they contain lenticular beds, and more or less 

 thick sheets of aqueous deposits — in some places the stony clays even exhibiting a 

 kind of stratification — and ever and anon such water-assorted materials are com- 

 mingled with stony clay in the most complex manner. These latter appearances 

 are, however, upon the whole best developed upon the low grounds that sweep out 

 from the base of the Alps. The only question concerning the ground-moraines that 

 has recently given rise to much discussion is the origin of the materials themselves. 

 It is obvious that there are only three possible modes in which those materials 

 could have been introduced to the ground-moraine: either they consist of superficial 

 morainic d(5hris which has found its way down to the bottom of the old glaciers by 

 crevasses ; or they may be made up of the rock-rubbish, shingle, gravel, kc, which 

 doubtless strewed the valleys before these were occupied by ice ; or, lastly, they 

 may have been derived in cliief measure from the underlying rocks themselves by 

 the action of the ice tiiat overflowed them. The investigations of Penck, Blaas, 

 liiihm, and Bruckner appear to me to have demonstrated that the ground-moraines 

 are composed mostly of materials which have been detached from the underlying 

 rocks by the erosive action of the glaciers themselves. Their observations show 

 that the regions studied by them in great detail were almost completely buried 

 under ice, so that the accumulation of superficial moraines was for the most pail 

 impossible; and they advance a number of facts which prove positively that the 

 ground-moraines were formed and accumulated under ice. I cannot here recapitu- 

 late the evidence, but must content myself by a reference to the papers in whicii 



