OF THE UNITED STATES. 17 



a few exceptions, have also been found in the arenaceous 

 bed ; but many of the organic remains of the latter are not 

 observed in the limestone strata, which have not yielded 

 any multilocular univalves, unless the doubtful fossil, Be- 

 lemnites ? ambiguus, be of this character : neither do they 

 contain Terebratulse or Exogyrae. 



DELAWARE. 



Ferruginous Sand. In this state, the blue and gray 

 friable marls extend in the line of the Chesapeake and 

 Delaware canal, from St. Georges almost to the western 

 lock. St. Georges and its vicinity afford Gryphsea and 

 Exogyra in great numbers, with Ostrea falcata and some 

 Belemnites. The deep cut of the canal abounds in Am- 

 monites, Baculites, and Scaphites, without any of the 

 fossils previously mentioned. This locality consists of a 

 series of pyritous sands and clays, in which the shells have 

 decomposed, leaving only the casts. The excavation here 

 has been deeper than in any other locality, and a register 

 kept of its mineralogical and other features. I am in- 

 debted to Mr. A. A. Dexter, one of the Engineers, for two 

 vertical sections of the strata, one taken at the summit 

 level, the other about a quarter of a mile west of that 

 point. 



It will be observed that these sections are transverse 

 with respect to the canal, which runs nearly east and west. 



Section, No. 1. PL 14, upper figure. Deepest sec- 

 tion of the deep cut. Vertical depth, 82| feet. 



1. A series of white, yellow and brown sands and gravel, 



C 



