28 NEW YORK STATE MUSEUM 



"West River shale 



Fine, blue black or dark gray shales with thin bands of black 

 slaty shale at intervals of 2 to 6 feet. Spheric or oblong con- 

 cretions are common, occurring singly or in rows. A few thin, 

 sandy flags occur in the upper part of the beds. These shales 

 are contrasted with the Genesee shale below by their lighter shade 

 ?nd their much less bituminous character, for the most part being 

 highly fissile and breaking out into thin, sharp but small 

 laminae. The lighter parts of the mass are easily eroded, being 

 tenuous and clayey and the streams that flow down the hillside 

 have cut numberless narrow, deep gullies in them, the sides of 

 which are steep slopes of slippery shale. The concretions in the 

 shale are frequently highly characteristic and are the source of 

 most of the very abundant specimens of these bodies which are 

 found scattered over the region and have been collected by the 

 residents on account of their curious forms, suggestive of 

 turtles, human skulls, hats and various other rounded objects. 

 They not infrequently carry fossils in much better condition than 

 found elsewhere in the beds, and these fossils of the concretions 

 are more in accord with the singular fauna of the Genundewa 

 limestone than are those of the shales. In the shales organic re- 

 mains are of more frequent occurrence than in the Genesee shales 

 beneath but they are seldom abundant. 



This rock is shown in the lower part of all the ravines in the 

 Middlesex valley north of the Goodrich gully. There is also a 

 small outcrop by the roadside half a mile north of Rushville and 

 along several small brooks in the southwest part of the town 

 of Gorham. In the Snyder gully just above Woodville at the 

 head of Canandaigua lake they are well shown, and also in the 

 lake cliff at Woodville where their peculiar blocky structure, 

 due to numerous joints, is finely displayed. The deeper parts 

 of the ravines at Coye, Granger, Lapham, Cook and Hicks 

 points and all of the other gullies between the head of the lake 

 and Seneca point are in these shales; also the Seneca point 

 ravine above the first cascade and the upper part of Victoria 

 glen and Foster gully. Northerly exposures are also shown in 



