29S 



NEW YORK STATE MUSEUM 



Feet Total 



Ma nl i us limestone 4()-6(> 



Dark blue thin bedded limestone which breaks 

 into almost regular blocks. The fossils are : 



1 Tentaculites gyracanthus {Eaton) Hall aa 



2 Spirifer vamixemi Hall a 



3 Stroplieodonta (Brachyprion) varistriata (Con.) H. v 



4 Megambonia aviculoidea H. (?) c 



5 Leperditia alta (Con.) H. c 



6 Chaetetes (Monotrvpella) arbusculus H. c 



Covered by soil 2(3-20 



25 Summary of the stratigraphy of Becraft mountain and vicinity 

 near Hudson N. Y. 1 



In structure Becraft mountain is a synclinorium, 

 the axes of which pitch southward except near 

 the southern end where they rise again, through 

 faulting, thus forming a basin structure. 

 Along the eastern side the dip of the strata 

 averages about 12 degrees into the mountain, 

 but the western side shows a number of 

 asymmetric anticlinal folds with steep, often 

 overturned western limbs. The structure is 

 furthermore complicated by a number of faults 

 of which 21 have been definitely located. Sev- 

 eral of these faults present interesting over- 

 thrust features while repetition of the strata 

 is of common occurrence. The following forma- 

 tions occur: 



Feet Total 



Onondaga limestone 20-25 



This is found only in a synclinal trough forming 

 the high ground in the southeastern part of the 

 mountain. It is a dark gray, finely crystalline 

 lime sandrock; rare in fossils. Those recorded 

 arc : 



Chonophyllum Spirifer varicosus 



Favosites Atrypa reticularis 



Stromatopora Leptaena rhomboidalis 



Zapbrentis sp. Orthothetes pandora 



Odontccepbahis selenurus Euomphalus sp. 



Spirifer ruricosta 



This is the highest formation of Becraft moun- 

 tain. 



'(irnhnu. A W. Stral iirraphv of Reeraft Mountain. Columbia Co.. N. Y. 

 N. Y. State Paleontol. Rep't. 1903. p. 1030-70. 



