GEOLOGY AND PALEONTOLOGY OF THE SCHOHARIE VALLEY 311 



Holopea elongata Hall 



Laevidentaliiuii sp. ? 



Spirifer vaniixemi Hall v 



Leperditia alta Conrad c ; 



Holopea antiqua (Vanuxem) 



Zaphrentis sp. 'i ] 



Bed 17 is a veritable Stromatopora reef. Bed 18 



contains in the lower part the following fauna: : 



Spirifer vanuxemi Hall c 



Tentaciilites gyracanthus (Eaton) c 



Stropheoclonta varisti-iata Conrad c 



Leperditia alta Conrad c 



Ostracods, niimerons specimens of two or three species 



Hormotoma, small species 



Holopea elongata Hall 



Both faunas, above and below the Stromatopora bed 

 are specially characterized by the occurrence of 

 gastropods. 



Feet 



Rondout 20-31 



Chietly lime mudrocks^ mostly unfossiliferous, and 

 containing beds of workable cement. At Rondout 

 the following subdivision has been made by van 

 Ingen and Clark : 



Feet Inches 



fll Paving block or mud crack 3 B 



I 10 Prismatic or five point 4 4 



Upper with gray cement J 9 Leperditia bed 2 1 



8 Curly, variable 8-19 



7 Soft gray cement 3 3 



6 Hard gray cement 5 



5a Middle ledge '. 7 



Lower or dark cement beds ( 5 Hard black cement 4 8 



9 feet, 7 inches to 11 feet, •< 4 Soft black cement 4 5 



• 2 inches ( 3 Footledge 6" to 2 



Plartnagel and van Ingen and Clark have suggested that the 

 upper beds (6-11) alone represented the Rondout and that the 

 lower beds 3-5, represented the Rosendale cement beds, the seven 

 inch middle ledge (5a) representing the Cobleskill. I believe 

 however that the whole series here represents the Rondout and 

 that the underlying 5-7 feet of " Coralline limestone " which rests 

 directly on the upturned Hudson river sandstones in this region, 

 is the Cobleskill, while the Rosendale cement bed and the Wilbur 

 limestone are absent altogether. Both of these appear at the 

 Wilbur bridge section and south of Wilbur, where the Cobleskill 

 is 10-15 feet thick, which thickness it retains as far as Rosendale 

 or beyond. The Rondout cement above it is 19 feet thick at the 

 Wilbur bridge exclusive of the mud crack layer or five point bed. 

 At Eddyville the same bed is 7 feet thick exclusive of the five 

 point, the Cobleskill being 10 feet. 



beds 19 feet, 6 inches 



