REPORT ON THE GEOLOGY OF NORTH AMERICA. 



31 



Periods. 



Character of Formations. 



Banks of oyster shells, ascribed 

 to the Indians, contain oc- 

 casionally fragments of older 

 tertiary shells, as Pectens, 

 &c. ; matrix generally sandy, 

 like that of the beach. 



Diluvial. I Boulders.pebbles, and sand, de- 

 rived from the primary and 

 ancient secondary rocks of the 

 interior. No organic remains. 



Localities of the Formations. 



New Jersey; Choptank River, 

 Maryland; York River, 

 Virginia, &c. 



Surface of the United States 

 generally. 



Ancient Al- 

 luvial. 



Beds of clay and variegated 

 sands. One bed is a deep 

 black tenacious clay, con- 

 taining leaves, trunks of trees, 

 lignite, amber, and vegetable 

 products generally. It has 

 all the aspect of having been 

 once a saltwater marsh, si- 

 milar to that now at the mouth 

 of the Mississippi. No re- 

 mains but such as are sup- 

 posed to belong to existing 

 species have hitherto been 

 found in these clays, and they 

 are therefore, for the present, 

 put apart from the true ter- 

 tiary formations. 



Martha's Vineyard ; Long Is- 

 land ; greater part of New 

 Jersey from Amboy Bay 

 along the sections of the rail- 

 road to Bordentown; Chesa- 

 peake and Delaware Canal 

 in Delaware; Telegraph Hill, 

 Baltimore ; near the city of 

 Richmond, Virginia; Cape 

 Sable in the Chesapeake Bay, 

 Maryland. There is little 

 doubt that the same appears 

 interruptedly the whole way 

 to the Mississippi. 



Newer Plei- 



OCENE. 



Older Plei- 

 ocENE and 

 Meiocene. 



A lead-coloured clay. 



Mouth of the Potomac, St. 

 Mary's County, Maryland. 



Alternating beds of sand and 

 clay, the sandy beds often 

 abounding in fossil shells, 

 which are sometimes in a 

 friable and pulverulent state, 

 giving the bed the character 

 of a shell marl. These fos- 

 siliferous beds rest almost 

 invariably on a bed of blue 

 clay; sometimes the sands 

 are greenish, but more usu- 

 ally they are yellow with a 

 slight admixture of clay. 



Cumberland Comity, New Jer- 

 sey; Cantwell's Bridge, De- 

 laware ; Chester Town ; East- 

 on, and nearly all the eastern 

 shore of Maryland; the whole 

 of Charles, St. Mary's, Cal- 

 vert, and part of Prince 

 George Counties, Maryland. 

 In Virginia, in Lancaster, 

 Gloucester, and all the pen- 

 insula between James and 

 York rivers ; also nearly all 

 Norfolk, Nansemond, Isle of 

 Wight, Surrey, and Prince 

 George Counties. In North 

 Carolina, near the towns of 

 Wilmington, Murfreesboro', 

 and throughout the counties 

 of Craven,Duplin, &c., across 

 the State. In South Carolina, 

 Vances ferry on Santee river 

 seems to be about the termi- 

 nation of the middle tertiary 

 groups of the United States. 



