OF MARYLAND. 53 



which large quantities of alum and copperas are annually 

 manufactured for the supply of nearly the whole Union. 



On the Eastern Shore, the secondary formation extends to 

 the Chester river, comprising the lower portions of Cecil and 

 nearly the whole of Kent, that portion alone of tiie latter county 

 forming the eastern neck, and some of the necks of level land 

 in this direction being excepted. The materials of this forma- 

 tion are a highly ferruginous sand, green sand, and micaceous 

 black sand, irregularly deposited, frequently intermixed, in 

 some places uncovered, in others overlaid by gravel, and thick 

 beds of erratic masses consisting principally of hornblende and 

 quartz rocks. The fossils that occur in the green sand are 

 Terebratidm and the GryphcBa vomer ; in the micaceous black 

 sand, there have been found the Exogyra, Ostrea falcata^ 

 casts of Cuculloea Mortonii, fragments of ATunioniies, the tooth 

 of a saurian reptile, claws of a species of crab. Lignites, with 

 other undetermined organic bodies, and in some localities 

 pyrites and crystals of selenite. The tertiary deposites lie 

 south of the Chester river, and do not extend further than the 

 Choptank, inclining in the same direction ; so that in the upper 

 portions they are found several feet above tide, whereas, in the 

 lower parts, as in the necks of Talbot county, they appear but 

 little above the water-line. Beyond the Choptank, in Dor- 

 chester county, they have been reached at the depth of forty- 

 five feet. At the head of the north-west fork of the Nanticoke, 

 there occurs a fossil deposite, consisting of the Ostrea Virgi- 

 nica, Mytilus hamatus and Nassa obsoleta ; and in the vicinity 

 of Easton one composed entirely of Ostrea Virgittica, depo- 

 sited in the midst, as it were, of older ones containing nume- 

 rous species of marine shells. The upper portions of the 

 lowest counties are very sandy and rolling — a succession in 

 fact of sand-hills gently inclining to the south-west and termi- 

 nating in a level deposite of stiff clay — as if at one time this 

 part of the country had been a sea-beach, from which the 

 waters have receded to a considerable distance beyond the 

 mud-flats that formed at the same period of time, the shallow 

 bottom of the ocean, and extended several miles from her 

 shores. No fossils are known to occur in this direction, the 

 other interesting geological features of which, are embraced in 

 the account of its physical geography. 



