240 



J. G. NEWSOM CLASTIC DIKES 



The main bituminous bed 

 of this locality, and the one 

 from which the intrusion at 

 25 was probably derived, is 

 shown in black at the bQt- 

 tom of the picture. 



At the Side Hill quarry 

 (26, figure 6) is a fine expos- 

 ure of an intrusion which 

 cuts some 30 feet of diatom- 

 aceous shale overlying the 

 bituminous sand bed. The 

 dike is connected with the 

 underlying bituminous 

 sand bed, as shown in figure 

 1, plate 24; it varies in 

 thickness from 2i feet near 

 its top, 30 feet above the 

 parent sand, to 6 feet in its 

 thickest part, a few feet from 

 the place where it unites 

 with the underlying sand- 

 stone. 



At Rattlesnake quarr}^ 

 (27, figure 6) the overlying 

 shales are greatly fractured, 

 and along the fractures are 

 many bituminous sand in- 

 trusions, which cut the 

 shales at all angles from 

 degrees to 65 degrees, and 

 are in many cases directly 

 connected with the under- 

 lying sandstone. In thick- 

 ness the intrusions vary 

 from mere stringers to a 

 15-foot, jumbled mass of 

 bituminized sand with in- 

 cluded shale fragments, 

 which extends 8 leet up 

 into the shales. 



