128 Organic Remains of the 



Art. XL — Supplement to the " Synopsis of the Organic Remains 

 of the Ferruginous Sand Formation of the United States ;" by 

 S. G. Morton, M. D. 



(Continued from Vol. XXIII, p. 294.) 



The recent discovery of the Middle Tertiary, or London clay 

 formation, in Alabama, completes the Tertiary series of the United 

 States ; and this series, as we have before seen, is based, as in Eu- 

 rope, on the Cretaceous* group. No member of the Oolitic series 

 has yet been identified by fossils ; and all our known formations 

 above the Medial order, are embraced in the following diagram ; for 

 our so called New Red Sandstone and Oolitic strata can have no 

 other than a hypothetical existence, until their organic characters are 

 established. 



Tiyr 1 < Alluvial. 

 • ^°^^^°1 Diluvial . 



C Upper Tertiary, (Up. Marine.) 

 Tertiary < Middle Tertiary, (London Clay.) 

 ( Lower Tertiary, (Plastic Clay.) 



q 1 ( Calcareous Strata. ) Cretaceous group, or Ferrugin- 

 ^ ( Ferruginous Sand. ) ous Sand series. 



Although no known section exhibits all these strata in conjunction, 

 yet more or less of them are constantly observed in proximity. It 

 often happens that the ferruginous sand is covered only by alluvial 

 deposits, or by diluvial gravels and sand : near Wilmington, N. C. it 

 is immediately overlaid by the upper tertiary formation ; at Borden- 

 town, N. J. plastic clay forms the superincumbent mass ; and if I 

 may judge from the organic remains I have received from Alabama, 

 the secondary beds are surmounted by a vast deposit of middle ter- 

 tiary fossils, the analogues of those found in the calcaire grassier of 

 Europe. 



With respect to the basis on which the ferruginous sand rests, we 

 as yet know nothing with certainty ; for although these strata have 

 been penetrated nearly one hundred feet at the Chesapeake and 



* This term is now, with great propriety and by common consent, applied to the 

 whole Chalk formation, and of course embraces our Ferruginous Sand. 



