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 marie,) 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 thai 

 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, &e. 



I am not able to refer definitely to Brongniart's point of subdi- 

 vision of his secondary formation into ypper and lower secondary. 

 It is at the meeting of the foreign lias 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 Jersey, near the south line of Orange county, 



* The opinion of these eminent men in support of Dr. Morton's views, has been fully 

 expressed in this Journal. 



