Reviews. 



Correlation Papers. The Newark System. By Israel Cook Russell. 

 Bulletin 85, U. S. Geological Survey. Washington, 1892. 



This Bulletin adds another number to the list of invaluable correl- 

 ation papers, prepared especially for the Geological Survey, but of the 

 greatest service to all professional geologists and advanced students 

 alike. Prof. Russell's paper is of exceptional completeness from the 

 bibliographical side; its index is a marvel of minute reference; every 

 author's name is followed by a complete list of his writings, the more 

 important ones being analyzed ; every locality noticed in any paper is 

 indexed separately, with reference to the place of its mention ; occur- 

 rences of sandstone, shale, conglomerate and trap are catalogued under 

 these headings. Immediate reference may thus be made to any desired 

 item concerning the Newark system, excepting the fossils, which, for 

 some reason, are not indexed under their names, but only through the 

 authors who have described them. 



The chief headings of the text are : Nomenclature, area, lithology 

 and stratigraphy, conditions of deposition, life records, associated 

 igneous rocks, deformation, former extent, correlation and summary. 

 A good number of maps serve to guide the reader to the easy under- 

 standing of the several areas into which the formation is divided. I 

 can only comment on a few of these subjects. 



Professor Russell has done good service in the fourth headings in 

 showing the incompleteness of the evidence on which glacial action has 

 been argued as an agency in the deposition of the formation. Near 

 the margin of several of the Newark areas, heavy conglomerates, con- 

 taining boulders up to four or five feet in diameter, are known at vari- 

 ous localities ; and although none of these deposits are unstratified, 

 they have frequently been appealed to as evidence of glacial action. 

 But none of the boulders are scratched or notably angular; all of them 

 are, as far as known, deposited near the shore of their time ; all of them 

 are systematically interbedded with ordinary aqueous deposits. Cer- 



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