APPENDIX. 



Observations on the Geology of York County, Pennsyl- 

 vania, by Thos. G. Clemson ? read October 29, 1834. 



To the President and Members of the Geological Society of Penn- 

 sylvania. 



Gentlemen. — We, the undersigned, having had the honour 

 to be nominated by this society for the purpose of examining 

 certain formations in the district called York County, in the 

 state of Pennsylvania, proceeded thence, and now beg leave to 

 offer the following observations : 



The honourable members of the society are w 7 ell aware, that 

 a thorough scientific examination of any district of country 

 would require the united endeavours of several, or the long 

 continued observations of one well educated upon a multiplicity 

 of sciences, all more or less included in the now comprehensive 

 term geology. The mineral constitution of any portion of the 

 earthy surface can only be successfully developed after indefa- 

 tigable, mature, and multiplied examination, of all points, and 

 these results compared with new and distant appearances. The 

 naturalist's attainments should be great, his physical at- 

 tendants the hammer, the compass, and almost a laboratory. 

 No stone should be left untried, no ravine, no excavation unex- 

 amined ; the mineral constituents, the fossil contents should be 

 well classed; and after the profound consideration of these, 

 with many other characters, the observer may come to a just 

 conclusion of the nature, geological position of one or more 

 distinct particular formations. 



His first aim should be to fix upon some distinct member of 

 the geological series, whose position has been well determined : 

 this must be his north star, and it is only by constant refer- 



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