GEOLOGICAL SECTION OF NEW JERSEY Bu8 
Clark! 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 ran- 
ging from the Eocene to the Hornerstown marl, while in the southern 
portion outliers are found upon the Mount Laurel sand. 
Kirkwood jormationUnder 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 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 too feet or more along the outcrop. On the basis of the abun- 
dant fauna in the beds at Shiloh, the Kirkwood is believed to corre- 
spond in a general way with the Calvert formation 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. At Atlantic 
City clays, sands, and marls from 390 to 1,225 feet below tide carry 
Miocene fossils, and at Wildwood those from 300 feet to 1,090 feet 
and perhaps to 1,244 are Miocene. From the fossils it is evident that 
strata referable to the St. Marys, Choptank, and Calvert horizons 
of the Chesapeake group are present. 
Cohansey sand.—Overlying the Kirkwood at its outcrop is a 
formation composed chiefly of quartz sand, locally with laminae and 
" Report of the State Geologist of New Jersey, for 1893, p. 346. 
