240 THE JOURNAL OF GEOLOGY. 



Hook. The text contains an historical sketch in which the work of past inves- 

 tigators is briefly cited, and reference made to the various views upon the 

 classification and correlation of the several formations. A second chapter 

 is devoted to a consideration of the physical features of the coastal plain, fol- 

 lowing which is an extended statement in regard to the stratigraphical char- 

 acteristics of the formations found there. Although an attempt is made to make 

 the classification of the deposits coincide, so far as it is possible, with the inves- 

 tigations of the late Professor Cook, yet some changes of importance are con- 

 sidered to be necessary. The name Raritan formation is proposed in place of 

 the wholly inadequate term Plastic Clay, and the Upper Marl bed, which is in 

 part Cretaceous and in part Eocene, is divided into Manasquan Marl and 

 Shark River Marl respectively. The division of Yellow Sand proposed 

 by Professor Cook is not held to be an independent formation, but is included 

 under the Manasquan Marl. The Miocene is considered to be extensively 

 developed in New Jersey. Although fossils have been found at only a few 

 points, they are thought to be sufficient in number to indicate a series of depos- 

 its several hundred feet in thickness and many square miles in surface exposure. 



In summing up his statements in regard to the relation of the several 

 formations. Professor Clark says, "the deposits of the coastal series of New 

 Jersey show complete conformity from the bottom of the Raritan formation to 

 the top of the Upper Marl bed, while no wide-reaching dislocations of the 

 strata have been observed at any point. The strike follows a nearly continu- 

 ous trend of N. 50 E., while the dip is twenty-five to thirty feet in the mile to 

 the southeast. Overlying the Upper Marl bed unconformably is the Miocene, 

 which possesses the same general structural and stratigraphical features as the 

 earlier members of the series." 



The origin of greensand, which characterizes so many of the coastal plain 

 formations of New Jersey, is fully considered, the results by Professors Murray 

 and Renard, of the Challenger Expedition, being given with much fullness. 

 The geological distribution of greensand is briefly reviewed, and the character 

 of the New Jersey deposits more fully considered. Three colored plates are 

 reproduced from the Challenger Expedition report on Deep-Sea Deposits, to 

 illustrate the mode of formation of glauconite. R. D. S. 



The Pleistocene Rock Gorges of Northwestern Illinois. By Oscar H. 

 Hershey. American Geologist, November, 1893. 

 The object of this paper is to ascertain the length of the " deglaciation inter- 

 val and perhaps interglacial epoch." The ice of the maximum period of gla- 

 ciation affected this region but slightly. In some cases the glacial sand and 

 gravels were deposited in ridges transverse to the streams' courses, thus dam- 

 ming the streams and producing small lakes. Sometimes the barriers were so 



