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tral and southern Maryland, upon the lower members of the 
Potomac group which are not represented in New Jersey. 
Elsewhere in New Jersey the upper Raritan consists of white 
sands or fine gravel and the line of contact is sharp, except 
where it is obscured by Tertiary or later deposits. The Mat- 
awan is conformably overlain by the lower Monmouth forma- 
tion; the lithological differences are clearly marked, however. 
In its northern portion the Matawan is readily separable 
upon lithological grounds into Crosswicks Clays and Hazlet 
Sands; outside of New Jersey in Delaware and Maryland 
these divisions cannot be recognized with any certainty. 
The Crosswicks Clays consist of slate or drab-colored clays 
with thin seams and pockets of glauconite, becoming dark, 
almost black, locally interstratified with white sand, contain- 
ing much lignite and beds of leaves on Raritan Bay. The 
lignified trunk of a large tree was found in the clays in this 
vicinity, as well as many fragments. Further southward the 
clays become brittle, more arenaceous and micaceous and 
contain less iron sulphide. The Hazlet Sands are highly 
ferruginous, brown in color, with indurated crusts in their 
lower layers; above these there is frequently a well-developed 
layer of dark-colored clay, overlain with very micaceous 
sands, which are sometimes dark-colored, especially toward 
the south where they are also argillaceous. 
In his report on surface geology Professor R. D. Salisbury 
states * that his assistant, Mr. G. N. Knapp, distinguished five 
layers in the clay-marls and traced them across the state. 
These he designates Merchantville bed (marly clay), Wood- 
bury bed (dove-colored clay), Columbus bed (sand), Mar- 
shalltown bed (marly-clay sand), and Wenonah bed (sand). 
These features, although more or less marked, are not sharply 
defined throughout the entire area of the Matawan, and Pro- 
fessor Clark has never attempted to name or map any subdi- 
visions other than the lower clay member and the upper sandy 
member. 
The Matawan is abundantly fossiliferous, especially along 
* Ann. Rep. State Geol. N. J. 1898: 35. 1899. 
