i4 CRETACEOUS AND TERTIARY FISH. 



upon the "ash" marl of the Manasquan. The conformity, how- 

 ever, is only apparent, well-borings indicating that the Shark 

 River, as this formation has been called, probably overlaps the 

 Cretaceous. Clark 1 considers that it is not possible to correlate 

 the Shark River marl with any other known Eocene deposits and 

 regards them as probably older than the Eocene of Maryland. 

 By some other authors, however, they have been placed above 

 the Maryland Eocene. 



MIOCENE) SYSTEM. 



Beds of known Miocene age are widely distributed in the 

 coastal-plain portion of New Jersey, where they overlap the 

 Eocene and many of the Cretaceous formations. At the north 

 they rest on beds ranging from the Eocene to the Hornerstown 

 marl, while in the southern portion outliers are found upon the 

 Mount Laurel sand. 



Kirkwood formation. — Under the term Kirkwood have been 

 included all beds of demonstrable Miocene age which outcrop in 

 New Jersey. These beds vary lithologically in different regions, 

 but they are predominantly fine micaceous quartz sands often deli- 

 cately banded in shades of salmon-pink and yellow. Black, 

 lignitic clays occur in many localities at or near the base. In the 

 southern portion (Salem and the adjoining portion of Cumber- 

 land County) a thick (80-90 feet) bed of chocolate or drab- 

 colored clay occurs, above which there are (or were formerly) 

 exposures of a fine clayey sand containing great numbers of shells 

 (the Shiloh marl of many reports), which, in the localities where 

 it occurs, forms the upper bed of the Kirkwood. The thickness 

 is about 100 feet or more along the outcrop. On the basis of the 

 abundant invertebrate fauna in the beds at Shiloh, the Kirkwood 

 is believed to correspond in a general way with the Calvert for- 

 mation of Maryland, the lowest division of the Chesapeake group. 



Well-borings at Atlantic City, Wildwood and other points 

 along the coast have demonstrated the presence there of a great 

 thickness of Miocene strata not apparently represented in outcrop. 



1 Report of the State Geologist of New Jersey for 1S93, p. 346. 



