514 REVIEWS 



of New Jersey. It is such a presentation of glacial geology as will be of much use in 

 class work in universities and colleges, and at the same time is of interest and easy 

 comprehension to the general reader. The reviewer hesitates to refer to certain mis- 

 leading statements (which appear on pp. 183-86) in a work which otherwise is so 

 accurate and comprehensive. The lowan drift is but little more weathered and 

 eroded than the Wisconsin, and cannot be separated from it by the long interval men- 

 tioned in this report. The Illinoian drift-sheet which in this report is doubtfully 

 admitted to rank with the Kansan, lowan, and Wisconsin, really marks the culmina- 

 tion of the Labrador ice-field, and is no more due to a local advance than is the 

 Kansan drift-sheet which marks the culmination of the Keewatin icefield. 



The discussion of local details opens with a description of the terminal moraine 

 of the Wisconsin drift-sheet throughout its course across New Jersey, after which are 

 considered in turn the drift of the Appalachian province, of the Highlands, and of the 

 Triassic plain, in each of the several phases which are exhibited. Recessional 

 moraines were traced for short distances in the Appalachian province and in the Tri- 

 assic plain, but the tracing was not carried far enough to bring out, as has been done 

 in states west of the Appalachians, the successive positions of the ice-border in its 

 retreat. It appears from the scant notice given these later moraines that they consti- 

 tute very inconspicuous features. After discussing the drift north of the terminal 

 moraine, the stratified drift of late glacial or Wisconsin age lying south of the 

 moraine is considered. It includes not only valley gravel and overwash gravel plains, 

 but also lacustrine clays and silts, subaqueous overwash, kames, and certain deposits 

 attributed to icebergs. 



An old sheet of extra morainic drift, which has been described somewhat fully in 

 the Reports of Progress for 1892 and 1893, is briefly considered in this final report. It 

 is found to be discontinuous or patchy, and in this respect is strikingly in contrast 

 with the drift-sheet north of the moraine. It is estimated that about four-fifths of the 

 surface north of the moraine is deeply covered with drift, while about the same pro- 

 portion south of the moraine is nearly destitute of drift. In lithological make-up the 

 extramorainic drift is not greatly different from the drift in and north of the moraine. 

 But much of it is more highly oxidized and weathered than the moraine and drift- 

 sheet to the north. It is thought that the most highly weathered drift is at least as old 

 as the Kansan drift of the western states. 



MARYLAND. 



Shattuck, George B. The Pleistocene Problem of the North Atlatttic 

 Coastal Plain. Johns Hopkins Circulars No. 152, May, igoi; also Am. 

 Geol., Vol. XXVIII, pp. 87-107, 1901. 



Results of studies by McGee, Darton, and Salisbury are reviewed and attention 

 called to lack of harmony in the interpretations, and to changing views that have 

 been advanced. The author fails to find evidence of such complexity as his prede- 

 cessors have discovered, and considers the simple interpretation of marine action at 

 different levels sufficient to account for all the phenomena. Certain features which 

 one of his predecessors had interpreted to be unconformities pointing to a period of 

 elevation and subaerial erosion the author thinks to be due to slight changes in cur- 

 rent or freshet conditions differing in no way from the ordinary cross-bedded struc- 

 ture. An excursion into New Jersey confirmed the author in his view that the simple 



