1192 



NEW YORK STATE MUSEUM 



organic remains, which are exceedingly abundant, can be col- 

 lected only with great difficulty. The lower portion of the 

 Becraft is a bluish gray limestone traversed by many thin shale 

 films which intersect the main bedding planes at small angles. 

 The middle portion of the Becraft is a massive bed of hard 

 light gray, white or pink crystalline limestone, 18 to 20 feet 

 thick, made up entirely of organic remains, and running from 

 94 to 97$ of lime carbonate. 



It is very homogeneous throughout and is accordingly one of 

 the most resistant members of the series, and has suffered a 

 smaller amount of deformation; though it is faulted and folded 

 in considerable degree, it has no slaty cleavage. Both the upper 

 and lower portions of the Becraft are of darker color and are 

 traversed by thin shale films. These shale films seem to have 

 afforded lines of weakness along which movements due to lateral 

 compression have taken place, and these portions of the Becraft 

 are accordingly more broken up than is the middle. 



The lower dark gray Becraft constitutes a series of limestone 

 beds 104-feet thick which graduate nicely into the thinner layers 

 of limestone forming the subjacent New Scotland beds. There 

 is however a well marked division plane between the two forma- 

 tions. 



The upper Becraft, 6-f-feet thick, of somewhat darker gray lime- 

 stone, traversed by films of darker shale, anticipates the condi- 

 tions seen in the next overlying formation, the Port Ewen beds, 

 and its upper limit is marked by a prominent division plane. 

 The entire formation is replete with fossils, but the fauna has 

 not yet been well worked out. At a few favorable points fairly 

 good silicified fossils have been collected, but as a rule diagene 

 sis within the limestone sediments has rendered the organic 

 remains so indistinct that the majority of them can do! be 

 identified. 



This limestone is of considerable economic importance and lias 

 been largely quarried in this vicinity, as well as to the south- 

 ward and northward from here, for the high grade of lime which 

 it produces when burned. The lighter colored white or pink mid- 

 dle ledge furnishes the best lime. The vertical cut on the west 

 side of Hie Vlightberg, Gross's quarry on Delaware avenue, and 



