REPORT ON THE GEOLOGY OF NORTH AMERICA. 65 



not this be another result of the long dormant state of the vol- 

 canic forces in this hemisphere ? It has been a received doc- 

 trine, I believe, that igneous action has had much to do with 

 giving solubility to so vast a mass of silica and carbonate of 

 lime, which are regarded in the chalk formation as having been 

 produced rather in the state of a chemical precipitate than in 

 that of a mechanical sediment. 



The following recapitulation of the leading facts and deduc- 

 tions brought forward in the foregoing survey of our superior 

 secondary formations, will assist in elucidating more clearly the 

 present state of this portion of our geology. 



1 . The deposits of New Jersey differ from those of the South- 

 ern States in being chiefly arenaceous, and in containing an 

 immense quantity of the pure chloritic mineral called green- 

 sand. 



2. The organic remains hitherto discovered are nearly all, 

 with the exception of one or two species, peculiar to this con- 

 tinent. 



3. The existence of great quantities of lignite, of the remains 

 of Scolopax, a shore bird, and the position of these beds in New 

 Jersey, contiguous to the primary boundary or ancient coast, all 

 indicate that they were deposited in a comparatively shallow 

 sea, analogous in position to the present extensive line of sound- 

 ings which skirts the coast. 



The obvious shallowness of the portion of the secondary 

 ocean where these beds were formed, may perhaps help to ex- 

 plain the remarkable discordance alluded to between the Ame- 

 rican and European marine species of this period. 



4. The calcareous masses of Alabama, at least the upper 

 beds, are probably different in age from the marls and arena- 

 ceous beds of New Jersey. 



5. The marl formation of New Jersey is, perhaps, most nearly 

 represented by the European greensands. The limestone de- 

 posits of the South, on the other hand, resemble more the upper 

 members of the cretaceous group ; for example, the formation 

 of the plateau of Maestricht. 



6. Thus far there is no evidence of the existence of true chalk 

 in North America. Genuine flints have not yet been found in 

 any bed. 



7. Volcanic forces, during this period, seem to have been 

 nearly dormant, which may perhaps assist in accounting for 

 the absence of the chalk. 



8. The want of accordance, both in organic remains and 

 mineral character, between these beds and the cretaceous group 

 of Europe ; the difficulty of deciding their identity at present 



1834. F 



