206 TKANSACTIONS OF THE [1892 



of the mass have been thrown about in breaking apart, 

 and remain as brown sand spread along the lower levels. 

 The greater part of this marl has been mixed with the de- 

 posits of other series. It is distributed in chunks and 

 small pieces through the surface of the vari-colored clays 

 which form the base of the section, and it is, in places, 

 thickly studded with gravel and broken stones which have 

 fallen from the Quarternary beds near the summit of the 

 hill. Here and there the bones of Miocene cetacea, frag- 

 ments of shells, and the teeth of the Carcharodon are 

 found sticking in the surface ; but deep in the body of this 

 material are the fossils which establish its proper age. 

 Three feet beneath its surface the writer has met with dis- 

 tinct casts of Exogyra, Gryphea and Cucullea, coprolitesf 

 bones of reptiles, fragments of chelonians, and teeth of the 

 shark Otodus. The component elements of this marl agree 

 precisely with those of the Lower Marl of New JerSey and 

 Maryland, and like them have a nearly horizontal arrange- 

 ment of particles, which is visible in the plane of bedding. 

 A line of fossils in the body of the most westward of these 

 long beds coincides with the sloping direction of the heap, 

 and helps to show that slipping rather than overthrow has de- 

 termined its present position. This marl also rests, as in the 

 States above mentioned, directly upon the white sand of the 

 Alternate Clay-Sand series. This series is the upper group 

 which has been placed by New York geologists as a part 

 of the Amboy Clays, but which we now find to be laid 

 down unconformably upon the Woodbridge and Amboy 

 clays in New Jersey, and upon the Yariegated Clays in 

 Martha's Yineyard, 



It therefore seems necessary to designate this sharply 

 separated group by a name as the Raritan Formation, from 

 the river upon the shores of which it is so extensively and 

 typically exposed. It covers a very irregular stretch of 

 surface and varies in base-level according to the thickness 



