292 Organic Remains of the Ferruginous 



doubtful if there be any zoological analogies between the London 

 clay and the marls of New Jersey, Sic. 



I shall next offer a quotation from another celebrated naturalist, to 

 shew the analogy between tlie latter formation and the green sands 

 of Europe. I allude to Mr. Parkinson, a gentleman who has few ri- 

 vals in the knowledge of organic remains. Speaking of the genus 

 Spatangus, he observes — " The green sand presents some very curi- 

 ous and interesting facts respecting these fossils. In the water which 

 deposited this formation, the Spatangi appear to have first existed ; no 

 remains of this genus having been found in the subjacent formations. 

 It is also deserving of observation, that they are not found again but 

 in the chalk, and in the seas of the present world."* We have al- 

 ready seen that Spatangi are of frequent occurrence in the American 

 ferruginous sand ; and I shall dismiss this fact without further com- 

 ment. 



I have yet to offer a kw observations on a very interesting feature 

 of our marls ; I allude to the abundance of lignite and amber con- 

 tained in some of them, and especially, as already noted, in the low- 

 er mass of strata traversed by the Chesapeake and Delaware eanal. 

 We might at first be led to consider these substances as denoting a 

 plastic clay formation ; but when we observe that they are subjacent 

 to, and intermixed with, beds whose characteristic shells are extinct 

 genera of chambered univalves, and that these fossils do not occur as 

 insulated individuals, but on the contrary exist in surprising numbers, 

 must we not consider even these lignites and this amber as portions 

 of secondary strata? 



The occurrence of lignites is not unfrequent in the green sand of 

 Europe : and as analogies of geological arrangement in remote parts 

 of the world, are both instructive and interesting, I may be allowed 

 to adduce a few instances to the point in question. Thus, M. Boue 

 informs us that the marls which alternate with the green and ferru- 

 ginous sandstones, (gres ferrugineux et vert) below the chalk in the 

 South West of France, contain beds of lignite. f M. Boue further 

 remarks, that lignite and retinasphalt characterize the green sand for- 

 mation (Craie chloritee) at Obora, in Moravia. In allusion to these 

 lignites he says, " Ces bois montrent qu'ils ont ete longtemps sur la 

 rivage de la mer, puisq' ils sont converts d'huitres et de serpules et 



* Introd. to the Stiuly of Org-. Rem. p. 142. 



t Annales des Sciences Nat. (Paris) Tome 3, p. 309. 



