JEFFERSON COUNTY. 401 



LoRAiNE Shales. 



In the general description of the rocks of the Second district, I proposed to change the 

 name of this rock, substituting Loraine for Pulaski shales ; and though the latter had been 

 used in the annual reports, and there are objections to a change of name when it can be avoided, 

 or when no sufficient reason exists, still in this case it appeared to me that a change was 

 required ; for if the principle for local names is good, it is evident that the locality from which 

 the name is to be derived should be one where the most important characters of the rock are 

 best displayed. It was upon this ground that I proposed to substitute Loraine for Pulaski ; 

 the whole mass, with all the relations of tlie inferior and superior rocks, being exposed either 

 ^n the gulfs of Loraine, or in the adjacent country. If, therefore, a complete and satisfactory 

 knowledge is wished of this rock, it is necessary to visit Loraine. At Pulaski, the upper 

 part of the rock only is exposed ; but the deeper beds, those which give to the mass its 

 mineral characters, are not exposed at this place. There seemed, therefore, sufficient reasons 

 for the change proposed. 



In this mass, wc find a great diversity of materials. In this county they are composed of, 



1. Tliin even-bedcicci sandstone; grey internally, but becoming brjwnish or brown by weathering. 



2. A shaly sandstone, weathering as in the preceding. 



3. Fine grained, fragile slate, mostly argillaceous, and invariably exfoUating on being moistened or wet after havinw been 

 dried. 



4. Strata composed of calcareous matter and shale, varying from one to ten inches thick. They are mostly a mass of 



fossils, and become brown by weathering. 



5. A stratum of compact, fine-grained limestone, intermixed with carbonate or oxide of iron. This is from six to ten 

 inches thick ; and though it appears an unimportant part, yet it extends over a wide surface, and occupies a definite 

 position. It resembles the ironstone of the coal measures, and sometimes furnishes a mass in that curious form called 



a»ie m cone. 



The whole mass is characterized by alternating beds of shale and slate, with a great pre- 

 ponderance of the former. From the utica slate, for two or three hundred feet, thin grey 

 shaly sandstone predominates. In this part, a few fossils were found : one ortlioceratite, a stro- 

 phomena and pterinea. The strata consist usually of thin laminre bent or curved among them- 

 selves, partly in consequence of each individual layer thickening and thinning out, giving the 

 strata a waved appearance when worn. When used as a flagging stone, these layers present 

 this peculiar appearance. 



The change in mineral character from the utica slate is gradual, the slaty or argillaceous 

 strata are replaced slowly by those which are siliceous ; and though the steps of this change 

 may not in all cases be equal, yet we find in the end that the argillaceous matter disappears ; 

 as when the grey sandstone is formed, tliis substance is only found in small insulated masses, 

 but rarely in sufficient amount to form a continuous stratum. 



The boundaries of the loraine shales are well defined on their northern outcrop. 



From near Mannsville, the line of outcrop runs northeast, passing two and a half miles east 

 of Adams to Whitesville and Tylerville, whence, in two or tluree miles, it takes an easterly 

 direction, and passes from Jefferson to Lewis county. 



Geol. 2d Dist. 51 



