470 T. C. Brown — Shawangunk Conglomerate. 



of the contacts or transitions from bed to bed could not be 

 observed. 



In the gorge of Rondout Creek below the falls the JBinne- 

 water sandstone is approximately 50 feet thick. The upper 

 three or four feet is a white quartzitic sandstone similar to the 

 whole formation at Binnewater. Beneath this it consists of 

 alternating beds of shale and sandstone, gray to greenish in 

 color and very soft and friable. Many of the bedding planes 

 show ripple marks and sun cracks. The boundary between 

 this and the underlying shales is not distinct. The one forma- 

 tion passes gradually into the other, the sandy layers becoming 

 less prominent, and being replaced by proportionately more 

 and more shale. 



The High Falls shale consists of three practically distinct 

 members, an upper shale extending from the base of the Bin- 

 newater sandstone to the little fall at the old grist mill, a 

 middle sandstone twelve feet thick giving rise to this fall, and 

 a lower shale extending down to the Shawangunk con- 

 glomerate. The upper shale is mostly dark gray to black in 

 color, but it has a number of green shale beds and one dark 

 reddish colored bed several feet thick near its base. The 

 middle sandstone is almost black in color. The lower shale 

 consists of alternating green and red shales, the red color pre- 

 dominating. But even in this member the red is not as bril- 

 liant as in the Binnewater section. 



These three members can be distinctly recognized in the 

 cores from some of the drill holes. Their thickness in three of 

 the holes was as follows : 



Hole No. 



Upper shale 



Middle sandstone 



Lower shale 



12 



27 



15 



48 



10 



37 



13 



50 



32 



27 



12 



40 



Hole No. 6 did not penetrate the full thickness of the High 

 Falls shale. Moreover, the shale varied so much in both color 

 and texture in this hole that the division into members and 

 correlation with the other holes could not be carried out. Only 

 a few feet near the lower part of the core showed any red 

 color, while the greater part of the formation (60 feet) con- 

 sisted of a dark, almost black sandstone. Hole 32 also showed 

 only a few feet of shale with a dark reddish color, the rest 

 being dark green, dark gray, or black. 



Shafts 5, 6, 7, and 8 of the Rondout tunnel each penetrated 

 one or more of the beds under discussion. As these beds were 

 in every case opened up at a considerable distance beneath the 

 surface, where weathering had not reached the materials and 

 where circulating waters had not produced any important 

 effects, an exceptional opportunity was afforded to observe 



