REPORT ON THE GEOLOGY OF NORTH AMERICA. 21 



found forty-five or fifty feet beneath the city. It is seen in the 

 sections along the Delaware and Chesapeake Canal, where its 

 black tenacious vegetable clay and its sands precisely resemble 

 those above : also in the sections of the Newcastle and French- 

 town rail-road. Around the harbour of Baltimore these de- 

 posits occur on a large scale. In excavations made at Baltimore 

 abundant remains of trees and their fruits, particularly the black 

 walnut, have been found at the depth of forty-five or fifty feet. 

 In Virginia, along the same line, as at Richmond for example, 

 similar facts are well known. Near Baltimore, in sinking a well 

 in the Star Fort at Fort M'Henry, two miles below the granite 

 ridge, or supposed ancient coast, the workmen came upon a 

 mass of carbonized wood in a boggy marsh fifty feet below the 

 surface. In digging a well in the same Star Fort (perhaps the 

 same well), a tooth of the Mastodon was found at the depth of 

 nearly sixty feet. At a point on the Chesapeake Bay, about 

 twenty miles below Baltimore, called Cape Sable, very extensive 

 beds of these clays occur, abounding in lignite, pyrites, and 

 amber. The uppermost stratum is sand, very ferruginous, often 

 sixty or seventy feet thick, then a stratum of lignite three to 

 four feet. Below this a bed of sand, intermixed with enormous 

 quantities of pyrites, nests of this mineral occurring from a foot 

 to a foot and half in thickness, and of fifteen or twenty square 

 feet in surface. Next follows a bed' of earthy lignite, from five 

 to twelve feet deep, containing an abundance of pyritous wood, 

 with fragments of bituminous wood thirty feet long. In this 

 stratum of lignite have been also found specimens of a curious 

 comb or nest, the work of an insect. These are from one to 

 three inches in length : each cell has several minute holes. The 

 substance is a resinous matter, resembling amber in properties, 

 and the whole nidus is generally attached around a stem or car- 

 bonized twig. 



The next stratum is an argillaceous sandstone two to five feet 

 thick, uneven on its surface, while the beds above are all nearly 

 horizontal. Below is a bed of whitish grey clay four feet, and 

 beneath all a bed of sand. The enormous accumulation of car- 

 bonized trees in this place, now eighty miles in a direct line 

 from the sea, and at least fifteen from the supposed ancient 

 coast or boundary of primary rocks, points very clearly to the 

 existence, at some ancient date, of an extensive delta here. 

 Whether these beds at Cape Sable may hereafter be found con- 

 tinuous with those around Baltimore in which the Mastodon's 

 tooth was found, time will ascertain, but as yet we have no data 

 precise enough from which to infer the probable place of these 

 beds in the series. 



