Geology and Mineralogy. 87 



drawal and its relation to the glacial attitude of the land and" 

 postglacial changes of level have been inferred from rather too 

 Avidely scattered data ; and the conclusions thus reached were 

 perforce somewhat contradictory. The situation required ex- 

 tended and detailed investigation of the field from Manhattan to 

 the St. Lawrence. 



The distinguishing features of Prof. Woodworth's reports on 

 this area are their clear and dispassionate discussion of the 

 hypothesis of glacial retreat in a narrow valley and of the forma- 

 tion of associated marginal deposits (pp. 79-86, No. 84) ; and 

 the interpretation of complex deposits over an extended field. In 

 these respects the reports are justly comparable to Leverett's 

 Monographs on the glacial history of the Great Lakes region. 



To the student of glacial geology the method of work is quite 

 as interesting as the conclusions. It is found that the form of 

 the Hudson Valley influenced the retreat of the ice so strongly 

 that it is possible to outline the history of glacial retreat in terms 

 of the varying cross-section of the valley, taking into account the 

 order and arrangement of the deposits made either by ice or 

 tributary streams. In the Champlain region the evidence col- 

 lected is chiefly from the New York side of the lake and consists 

 of moraines, dry gorges and falls, spillways, beaches, bars, wave- 

 cut cliffs and benches, and marine shells. 



While the conclusions are based on a limited amount of field 

 work and cannot therefore be regarded as final on account of the 

 great extent of the field and the complexity of the details, they 

 nevertheless have a high value because of the discriminating 

 choice of sites critically examined for decisive evidence/ i. b. 



4. Geology and Water Resources of Oklahoma; by Charles 

 Newton Gould. Water-Supply and Irrigation Paper No. 148. 

 Pp. 118, with 32 plates and 32 figures. U. S. Geol. Survey. 

 Washington, 1905. — This report is as much of a geologic nature 

 as hydrographic and as such should be called to the attention of 

 geologists. The Wichita mountains in the southern part of the 

 territory consist of Archean and Lower Paleozoic formations and 

 are completely surrounded by Permian strata. The lower of 

 these "Red Beds" are believed to correspond chronologically 

 with Carboniferous limestones in Kansas. Many sections are 

 given showing the gypsum beds, and Prof. Gould believes the 

 Permian here to be wholly marine. The Tertiary deposits of the 

 High Plains and their relation to water supply are also discussed. 



J. B. 



5. Bulletins of the Geological Survey of Virginia ; Thomas 

 L. Watson, Geologist in charge. No. II. The Clay Deposits 

 of the Virginia Coastal Plain, by Heinrich Ries ; with a chap- 

 ter on The Geology of the Virginia Coastal Plain by William 

 Bullock Clark and Benjamtn Le Roy Miller. Pp. 184, with 

 15 plates. Board of Agriculture and Immigration, 1906. — This 

 is a thorough account of the clay occurrences and industry of 

 Virginia, rendered more interesting from the introduction on the 

 general geology of the Coastal Plain. 



