LANCASTER COUNTY. 465 



CHAPTER XIII. 



GEOLOGY OF LANCASTER COUNTY. 



For an extended view of the Geology of the county, we 

 "must refer to the final report of the general survey authorized 

 \)y the State government. 



In glancing over Mr. Scott's very beautiful and accurate map 

 of Lancaster county, it will be seen that the surface is broken 

 l3y irregular east and west ranges of hills, no one of which can 

 "be properly styled a mountain. Commencing at the south, 

 we find an extensive formation of primary stratified, or meta- 

 morphic rocks, such as mica slate and talcose slate, the latter 

 having garnets imbedded in it. These are quite abundant on 

 "the Susquehanna, below Pequea creek. Occasional patches 

 •of limestone* and clay slate occur, and the latter is extensively 

 worked for roofing purposes, at a place called Slate-hill. — 

 Ascending the river, we find the same formation extending to 

 Turkey-hill, where it terminates, about two miles below the 

 'Village of Washington, or about the fortieth parallel of latitude. 



The next rock in ascending order, is a close grained, very 

 Taard, siliceous sandstone, best seen at the mouth of the Chic- 

 quesalunga, between Columbia and Marietta, where it strikes 

 the Susquehanna in a bold bluff upwards of three hundred feet 

 in height. It is found at the opposite boundary of the county, 

 and extending into Berks, forms the hill on the south side of 

 Heading. A great deal of iron ore (argillaceous oxid and 

 hematite) has been taken from the clay overlying this forma- 

 tion, which although possessing some of the characters of the 

 preceding, such as large veins of quartz, and traces of fel- 

 .spar and tourmalin, may probably be looked upon as the 

 lowest of the transition, rather than the uppermost of the pri- 

 mary stratified. This conclusion, however, could scarcely be 

 .attained from an examination of the rock, limited to our own 

 localities. To understand it fully, it must be studied in thQ 

 .state of New York. 



*TvTo miles below the pfiouth of the Conestoga, for example, 



