436 REVIEWS 



Another chapter compiles in tabular form the salient features of the 

 geology of Pennsylvania. The author considers the much discussed 

 Wissahickon Gneiss as Ordovician in accordance with Rand^ and not as 

 pre-Cambrian as claimed by Bascom^ and by Bliss and Jonas.^ 



A pleasing feature of the book is its exceptional freedom from typo- 

 graphical errors, particularly when it is considered that so many proper 

 names have been used. A native of Chester County might offer the 

 objection that Comley Hall was a man, not a building (p. i68: ''field 

 northwest of Comley Hall"), or a German might criticize the spelling: 

 "regelmafsig," but remarkably few mistakes of this sort are to be noted. 

 The accuracy in the descriptions of localities will be best appreciated by 

 those who have spent days in trying to locate some overgrown exposure 

 from the vague information given by the older writers. 



A fuller table of contents would have added to the convenience of 

 the volume' — ^the one used consists of only seven lines. The index, 

 however, is adequate. 



Not only will the work be indispensable to Eastern mineralogists 

 and collectors but its mineral lists will prove of interest to economic 

 geologists. A recent paper on the chalcocite of Bristol, Connecticut, 

 has brought home the fact that much is to be learned from the old mines 

 of the Eastern States. Pennsylvania localities, with their unusually 

 complete lists of species and the elaborate suites of specimens available 

 in many museums, offer attractive opportunities for paragenetic studies. 



H. E. McKlNSTRY 



Casapalca, Peru 



Physiography and Glaciology of Middle West Greenland. Abstract 



of part of results of Swiss Greenland Expedition. By Alfred 



DE QuERVAiN, P. L. Mercanton, and others. Ergebnisse 



der Schweizerischen Gronlandexpedition, 1912-1913. Denk- 



schriften der Schweizerischen Naturforschenden Gesellschaft. 



Bd. 53. Zurich, 1920. Pp. 402, maps, diagr., photos. 



The physiographic studies made along the front of the inland ice of 



Greenland in the vicinity of Jakobshavn by the Swiss expedition, are of 



exceptional interest as showing the conditions which may have obtained 



on the glacial fronts of America and Europe not many thousand years 



'"Notes on the Geology of Southeastern Pennsylvania," Proc. Acad. Nat. Sci., 

 Phila. XLIV (1892), pp. 174-202. 



^ Philadelphia Folio, 162, U.S. Geol. Survey. 

 3 Prof. Paper 98-B, U.S Geol. Survey, 1916. 



