GEOLOGY AND PALEONTOLOGY OF THE SCHOHARIE VALLEY 113 



ally only one of these species is abundant on a given slab of the 

 rock. At intervals beds of a more arenaceous texture occur, the 

 material being' a moderately coarse lime sand. Such beds show- 

 much less of even bedding than do the mudrocks, and ripple 

 marks, cross bedding and other features so characteristic of 

 silicious sandrocks, are found, though the rock is entirely free 

 from quartz grains. Shaly beds, or beds of more or less cal- 

 careous clay mudrock also occur, though not very commonly nor 

 of great extent. They generally fill the interstices between lens- 

 like masses of lime sandrocks or lime mudrocks. 



In the Schoharie valley the best exposures of the Rondout and 

 Manlius beds are in the various quarries opened along the base of 

 East hill, east of the village of Schoharie. 1 The lowest beds of 

 the series, i. e. those following immediately on the Co'bleskill, are 

 best exposed in the Vrooman quarry, southeast of Schoharie post- 

 office. They are heavy bedded lime mudrocks, occasionally show- 

 ing a somewhat arenaceous texture, and containing worn frag- 

 ments of Favosites and Stromatopora. Complete heads of these 

 corals are also found in the more argillaceous parting shales. The 

 next higher beds are found in the Becker quarry below Laselle 

 park, just east of Schoharie aud in the lower Mix and O'Reilly 

 quarry at the stone crusher in the northeastern part of the village. 

 Here the thickness of the Rondout formation has been reported to 

 be 17 feet [pi. 8, 10]. 2 



In this locality some of the massive beds of the Rondout series 

 contain scattered geodes of calcite and of celestite. These geodes 

 are found occasionally in the stone fences in the northeastern part 

 of the village, and they are also well shown on the northern face 

 of West hill, where mining operations for the strontium mineral 

 were formerly carried on for some time. 



The higher Rondout beds are shown in the Mix and O'Reilly 

 quarry where they are succeeded by the fossiliferous Manlius. 

 These Manlius strata are also shown in the Becker quarry and in 

 the old quarry behind the cemetery easl of Schoharie court house. 



'For the details of these sections see chapter •">. 

 2 See section ch. 5, p. 239. 



