62 Gf 5 . REPORT OF PROGRESS. I. C. WHITE. 



These sandstone beds make cliffs everywhere throughout 

 the district, and are usually from 20' to 30' thick, succeed- 

 ing each other at intervals of 20' to 40' ; the intervals being 

 filled with beds of shale. 



Although seeming quite massive externally, from the long- 

 lines of cliffs which they form, yet when quarried into they 

 are usually found to be laminated in small regular layers, 

 from \" to 3" thick, and not at all corresponding to the 

 zigzag lines of the weathered surface. 



The color of the Catskill sandstone is usually a grayish- 

 green, varying to olive in the interior. 



Calcareous breccias : — Another very common character- 

 istic feature of the sandstone beds of the Catskill is the oc- 

 currence of a layer of calcareous breccia at their bases. 

 This feature is also seen in the Pocono sandstone formation 

 No. X although not so frequently. Sometimes these masses 

 thicken up to 5' and even 8', and then assume the appear- 

 ance of impure limestones. 



Mr. Vanuxem accurately described these layers thus : 

 u A peculiar accretionary or fragmentary mass, appearing 

 like fragments of hard slate, cemented by limestone. This 

 mass though usually but a few feet in thickness, where it is 

 thickest in the district, is a constant associate of the group. 

 It has not received a name with us, but is well known in 

 England by the name of cornstone ; and there also, from 

 what we read, it is confined to this group."* 



The calcareous breccias which everywhere accompany the 

 CatsMll rocks in this district, frequently contain pebbles of 

 sandstone, and sometimes of quartz. The pieces of slate 

 are nearly always of a dark olive hue, and present much the 

 appearance of a " slickensided " surface. They also fre- 

 quently contain what seem to be fragments of fish bones, so 

 broken and worn as to be indeterminable. The calcareous 

 matter often presents a fragmentary appearance, as though 

 it had been formed by the erosion and breaking up of an 

 older limestone. 



No valuable minerals occur in any appreciable quantity 

 in the Catskill rocks of the district. Thin strings or streaks 



* Geology of New York, 1844, Third District, p. 186. 



