REPORT OF THE STATE PALEONTOLOGIST 1902 973 



which extends upward from the base of the Wolf creek con- 

 glomerate lentil in the Olean region to a limonitic shale pres- 

 ently to be characterized, is regarded as a formation and to 

 it the name Cattaraugus is given. Two other conglomerate 

 lentils occur in it, the Salamanca and the Kilbuck. 



The bright red argillaceous shales of the Cattaraugus are 

 entirely different from the dark brick red or purplish shales of 

 the Chemung and need never be confused with them. No bright 

 red shales occur anywhere in this region below the Wolf creek 

 conglomerate but they do appear within a few feet above it. 

 They are usually fine grained and argillaceous though in many 

 places they become sandy and may locally pass into a thin red 

 argillaceous sandstone. Specially does this transition occur 

 in the southeastern part of the Olean area and in eastern 

 McKean county, Pa. It is not certain that the individual beds 

 ©f red shale are persistent or hold their thickness for more 

 than short distances, but it is certain that as one goes west- 

 ward into the Salamanca region and southwestward into War- 

 ren county, Pa. the beds of red shale tend to disappear. Their 

 disappearance appears to be due not to a lack of deposition 

 in this area at that time, nor to their once having been depos- 

 ited and subsequently removed from the entire region by 

 erosion before the deposition of the overlying formations but 

 to their grading over westward and southwestward into 

 deposits of other than red color. The stratigraphic equivalents 

 of the red shales are as a rule present to the westward but 

 their color has changed to olive-green, blue or drab. At the 

 same time there is some evidence that erosion occurred in this 

 region after the deposition of the beds containing these red 

 shales as will be seen somewhat later. 



The lighter colored shales interbedded with the red ones vary 

 from fine blue mud shales to light or dark green sandy ones. 

 Along with the shales are greenish gray, medium to fine 

 grained, soft, arkosic sandstones often thin or cross bedded 

 and with their parting planes flecked with mica particles. By 

 the oxidation of their iron content these sandstones weather 

 into a red soil just as the red shales do. These sandstones 

 lave been quarried and sawed into flagging at the Cook quarry 

 a few miles south of Olean, though no work is now being done 



