20 TALEONTOLOGY OF NEW JERSEY. 



micaceous beds, and, although several are apparently identical with forms 

 occurring in the Lower Marls, yet many of them are peculiar to these beds 

 as far as represented in New Jersey. 



Above the Lower ]\Iarls come the Middle Mai'l beds, characterized by 

 the yellow lime sands, filled in many places with Terel^ratula, and above 

 this the layers at the base of the Upper Green Marls, which contain a 

 fauna entirely distinct from those below, but still Cretaceous in its character. 

 Again, at the summit of the Upper Green Marls we find another distinct 

 fauna, representing the Eocene epoch of the more southern States and 

 ■affording many species identical with those from Claiborne, Alabama. 

 These mark six distinct zoological horizons, and if we divide the Lower 

 Marls from the Crosswicks and Haddonfield beds, as will possibly be done 

 when they are properly examined and studied, seven distinct horizons, six 

 of which may be classed as Cretaceous and one as Eocene. 



These zoological horizons conform very closely, if not exactly, to cer- 

 tain stratigraphical lines which were long since established by the State 

 geologist under the names of Raritan Clays, Camden Clays, Lower, Middle, 

 and Upper Marls, the last bed being mollusk-bearing only near the lower 

 and upper portions, which are respectively Cretaceous and Eocene. The 

 details of these beds can be found in the different annual reports of the 

 State survey, particularly in that of 1868, and in that on the clays of New 

 Jersey. 



Although between these zoological horizons there is little, and, indeed 

 almost no interchange of fossils, the faunas being almost entirely distinct, 

 the geological sequence is continuous, except between the Eocene or Upper 

 layers of the Upper Green Marls and the beds immediately below, where 

 there is a very slight unconformity, noticeable by close inspection, over 

 a very limited area only, and consisting principally of a slight denudation 

 of the top of the beds immediately below, before the deposition of the 

 Eocene Marls. 



It is not necessary here to consider in detail the structure of the layers 

 further than to mention that these different beds which are fossiliferous, 

 or moUusk bearing, consist at the base of the section of beds of clay of 



