To Tht American Geologist. January, 1894 
• 
Chamberlin and Leverett through Ohio, Indiana, and Illinois, and the 
nearly equal number described by Winchell and Upham in Minnesota, 
with their continuation west and northwest through the Dakotas and 
Manitoba, are doubtless referable to closely successive stages of halt or 
slight re-advance interrupting the recession of the ice-sheet at the end 
of the Glacial period. A similar series of retreatal moraines, already 
partially known, will probably be found traceable across northern 
Germany, northwestern Russia, southeastern Sweden, and Finland. 
Concerning the question whether the drift was carried forward 
chiefly beneath the ice-sheet or within its basal part, in the latter case 
becoming exposed on the surface near the ice-front by ablation, especially 
during the glacial retreat, the author presents only or mainly the hy- 
pothesis of subglacial transportation, while in this country englacial 
and finally superglacial transportation of much of the drift has been 
long maintained by Dana and many others. We also note that the loess 
is attributed chiefly to wind action, which appears true for portions of 
Asia; but the development of this formation in America, where it ex- 
tends along the course of the Missouri and Mississippi rivers, is very 
certainly due to deposition by broad river floods and lakes attending 
the departure of the ice-sheet. In Scotland the explanation recently 
given by Jamieson for the Parallel Roads of Glen Roy, that they were 
shores of lakes dammed by the waning Scottish ice-sheet, should prob- 
ably take the place of the old hypothesis of obstruction by local valley 
glaciers, which is here retained. Again, in seeking the causes of the 
glacial climate, only Dr. James CrolTs astronomical theory is adequately 
stated, and no space is given to the explanation by high uplifts of the 
lands that became ice-enveloped, which now is held to be most probable 
by nearly all American geologists, excepting those who think that some 
hitherto unsuggested cause remains to be discovered. It is mentioned, 
however, that Hutton accounts for the ancient glaciation of New Zea- 
land by such a high epierogenic uplift. 
The strange history of the Ice age, the descriptions of its records in 
all drift-covered regions, and the explanations of the origin of the widely 
varied drift formations, are very amply, clearly and interestingly pre- 
sented by this magnificent text-book. It was quite impracticable and 
needless, in a science so broad and now receiving so thorough and crit- 
cal investigation, to notice every phase of differing theories and opin- 
ions, or to bring the presentation in all cases exactly up to the present 
condition of knowledge. 
Notwithstanding the foregoing criticisms, we consider the work of 
Dr. Geikie. like Agamemnon among his warriors, "conspicuous among 
his equals," and /«//• excellence the best English text-book for American 
geologists. 
Ueber das Silurgebiet des Bottnischen Meeres. By Caul Wiman. 
(Bull, of the Geol. Inst, of Upsala, No. 1, vol. i, 1893.) 
The earliest of the palaeozoic faunas represented in this region is a 
Cambrian sandstone with Olenellus, Arionellus and Hyolithes. This is 
