252 The American Geologist. Octofjer, luuu 
REVIEW OF RECENT GEOLOGICAL 
LITERATURE. 
Glacial Erosian in (he Valley of the Ticino. By W. M. Davis. 
Appalachia, vol. ix, pp. 136-156, with six figures in the text and two- 
plates (views photographed); March, igoo. 
On the south side of the Alps, the formerly glaciated Ticino valley 
is cut steeply down 200 to 400 meters below the lower margin of gentle 
upper slopes at each side, upon which the peasants have their summer 
villages, with hayfields and pastures. The gently ascending upper 
tracts are regarded as continuations of the original or preglacial valley- 
floor, into which glacial erosion, more powerful because performed by 
deeper and faster flowing ice than at the sides, channeled the present 
precipitous inner valley. The courses of tributaries of the Ticino, on 
the gently inclined bights, before coming to the deep trough of glacial 
erosion, are called "hanging valleys" by Davis, adopting this term 
from Gilbert's studies, soon to be published, of Alaskan fjords and 
their similarly related tributaries. The same conditions also had been 
pointed out several years ago, by Prof. R. S. Tarr, in the case of 
Cayuga lake and others of the Finger lakes of central New York. It 
is thence inferred that glacial erosion generally, as by the entire North 
American ice-sheet, was more effective in determining the present 
topography of the country, its valleys and fjords, lake basins, etc., 
than has been before supposed by the author and by many other gla- 
cialists. w. u. 
The Geography of (he Region abou( Devil' s Lake and (he Dalles 
of (he Wisconsin, wi(h Notes on i(s Surface Geology. By R. D. Sa- 
lisbury and W. W. Atwood. Wisconsin Geological and Natural. 
History Survey, Bull. V. Educational Series I. 150 pages, 38 i)Iatcs, 
47 figures, 1899. 
This volume is intended for use in schools, and its plan is to treat 
fully and in an elementary way all general questions suggested by the 
details of the region. The Devil's Lake region is admirably suited to 
this purpose as it contains structural, topographic and glacial problems. 
Its striking scenery renders it of still greater interest and makes possi- 
ble the most desirable of educational media — good illustrations. Mr. 
Atwood's photographs and sketches are admirable, both artistically and 
geologically, and invariably illustrate the points which they are intend- 
ed to explain. 
In Part I the topography and surface geology are considered. The 
two Baraboo quartzyte ranges rise above an undulating plain. The 
ranges are of Upper Huronian age, highly metamorphic, and in some 
localities schistose. Resting unconformably upon this formation and 
forming the country rock of the plain are horizontal beds of Potsdan^ 
sandstone and of Lower Magnesian limestone. The topography is of 
two types — glacial and erosion. 
