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 Terebratule or Kxogyre. 
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 Gryphza 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. Iam 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, 824 feet. 
1. A series of white, yellow and brown sands and gravel, 
