VENUES: 
The Illinois Glacial Lobe. By FRank LEvEeRETT, Monograph 
XXXVIII, U. S. Geological Survey, pp. 817. Plates XXIV, 
9g figures. Washington, 1899. 
This is one of a series of monographs in course of preparation by 
the Glacial Division of the United States Geological Survey, whose 
purpose is to set forth the salient features of the glacial formations 
preparatory to more detailed mapping by quadrangles, which the sur- 
vey is undertaking, and by counties and other appropriate divisions, 
which many of thestates are prosecuting. In a sense it may be said to 
be the first monograph of the systematic series. “Two other monographs 
_ have been published, namely, that on Lake Agassiz, by Mr. Warren 
Upham, and that on the Glacial Gravels of Maine, by Professor George 
H. Stone, but these are special treatises on phenomena of exceptional 
interest and only indirectly form a part of the systematic series intended 
to cover the glacial area. The plan of the Survey departs somewhat 
widely from that prevalent in Europe where glacial work proceeds 
largely by minute studies of small areas without previous determination 
of the great features and broader classifications which can only be 
worked out by connected studies over large areas. The method of 
the United States Geological Survey has been to determine first these 
grand features and leading classifications and then descend in natural 
order to local details and more refined studies. Local mapping pro- 
ceeds at great disadvantage without such preliminary determinations, 
for such is the nature of the glacial formations that these larger 
expressions of the phenomena of the period are very imperfectly 
expressed within any restricted area, and are quite beyond satisfactory 
interpretation unless the studies are extended beyond them. 
The general reconnaissance work of the survey was essentially 
completed some years ago by the geologist in charge and the work of 
preparation of the monographs, as the second step of the plan, is now 
well under way. Besides the monograph under consideration, the 
manuscript of an additional one has been submitted and work upon a 
third is in progress. 
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