154 References to North American Localities. 
ersink. Most of the towns in the counties of Monmouth and 
Middlesex afford equally satisfactory illustrations; but they are 
not so open to inspection in all places. The uppermost of the 
secondary deposits is the cretaceous formation, most perfectly 
characterized ; but it contains no white chalk. The lowest of 
the tertiary is the plastic clay ; but the overlying marly clay and 
marine sand, generally including bog ore, &c., are most extensive. 
Dr. Morton sent numerous specimens of the cretaceous deposit 
to Brongniart and Mantell, with its organic remains ; and has also 
taken other means to put the question forever at rest.* Every 
potter-baker in New England, New York, and New Jersey, can 
testify to the character of the plastic clay, which rests on the green 
sand variety of the chalk (cretaceous) formation. 
The student, or geological surveyor, is requested to take a boat 
from South Amboy to Middletown Point, along the south shore 
of the bay. Here he will find lignite and minute specks of am- 
ber, embraced in plastic clay, and marly clay, (marine marle,) pre- 
cisely as described and drawn by Brongniart in his geological ta- 
bles. It is in some places at the water’s edge, at others high in 
the banks. He should then take a view of the two deposits 
within a circle of four or five miles, about Middletown Academy. 
He will be forcibly impressed with the geological history of that 
district. "The cretaceous formation seems to have been the up- 
permost deposit for many ages; and to have been moulded in- 
to rounded hillocks, with some gorges cut by rivulets and some by 
large streams. While in this state a new disturbing force threw 
upon it the plastic clay, the marly clay, and marine sand. In 
some places these new tertiary deposits did not cover the tops of 
the hillocks, but left rounded elevations of this secondary depos- 
it, higher than the more recent tertiary. 
If the student carries in his mind these views of the meeting 
of the two classes along the southern parts of Staten Island, Mar- 
tha’s Vineyard, &c., he will find numerous evidences of the same 
formation underlaid by red marl, sandstone, &c. 
~ Lam not able to refer definitely to Brongniart’s point of subdi- 
vision of his secondary formation into wpper and lower secondary- 
It is at the meeting of the foreign dias and Jura limestone. Bake- 
well says that lias clay separates oolite (of Jura limestone) from 
the lias beneath it. As genuine oolite has been found by Dr. 
Horton in New ron near the south line of Orange county, 
7 f Dr . Morton’ been fully 
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