'J4«^> TJtc American Geologist. ootobpr, \m\ 
Prof. T. C. Chamberlin opened the discussion by remarking that it was 
possible to classify these deposits upon three leases: 1. Structural; 2, 
Chronological; 3. Genetic. 
A sclieme of classification according to genesis was offered to the Con- 
gress in printed form and explained at length. 
Prof. (4:iudry spoke as follows: In the Parisian basin there are two 
different horizons distinguished by different faunas; the one indicating a 
cold, the other a warm climate. It is, however, impossible to decide 
which of these two periods was the earlier. In England the same con- 
dition of affairs is to be observed. In Germany there is but one Quater- 
nary fauna, which indicates a cold climate, whilst in Italy the fauna of 
the cold period is absent. 
Prof. II. Credner: The north German plain contains deposits closely 
related to those of the Pleistocene in America. Prof. Chamberlin's 
classification is admirable and wholly applicable to Germany. 
Baron de Geer expressed his approbation of the classification proposed 
by Prof. Chamberlin. He had for some years been advocating a similar 
classification for Scandinavia. A few minor alterations might be sug- 
gested to suit Scandinavian conditions; for instance, the marine deposits 
might be made a separate class; classes IV and V of Prof. Chamberlin 
could, perhaps, be reduced to sub-classes under III, as the formations 
frequently seem to be accidental or local. He agreed with the distinction 
suggested between osars and kames; that is, that the former are in the 
main radial and the latter peripheral with reference to the distribution 
of laud-ice. 
Prof. T. McK. Hughes pointed out that the classification given by Prof. 
Gaudry was purely chronological, whereas that suggested by Prof. 
Chamberlin was purely genetic. He then explained the abundance of 
striated boulders in one part of the glacial deposits and their absence in 
another. If the supplj' of material (that is, of rock bosses above the ice) 
ceases at any point, then all the boulders will gradually sink through the 
ice and become glaciated at the bottom. Prof. Huglies also thought 
that two distinct types of ridges formed of glacial material were con- 
fused \Hider the names: kames, osars and eskar. He also explained the 
"pitted plains" as due to an unusual interruption between the hills or 
ridges of eskar character. He expressed his opinion that the glacial 
period was a continuous one, in England at least, except for slight 
changes due to luiimportant oscillations. 
Dr. Walinschaffe advocated the chronological classification, and con- 
sidered such a one possible for the Quaternarj^ deposits of north Ger- 
many. These deposits begin wdth pie-glacial sands and gravels contain- 
ing Pidadina ^liliivuotii, which is still a living form and Liti>(/lyplnis 
nnloi'ouh'A. Above these follows a typical ground-moraine which is 
overlaid by stratified sand and gravel, containing the well-known diluvial 
fauna; and to these again succeeds the upper till, considered now as the 
ground-moraine of the second glacial epoch. 
AFTERNOON SESSION. 
Continuance of the same discussion. 
