216 



TRANSACTIONS OP THE 



FIRE CLAY 



Is coextensive with this mineral district, from the 

 Elk mountain to the opposite heights of the Armenia 

 mountain ; in beds of 1 to 3 feet thick. 



SILICIOUS CONGLOMERATES AND MILLSTONE GRIT 



Occur high up in the carboniferous series, but their 

 position is not uniform in all parts of the Blossburg coal 

 field. For instance, at Coal run, the conglomerate bed 

 occurs of the thickness of 18 feet at the height of 387 feet, 

 covering all the mineral beds. In Morris's run, a mile 

 and a half only distant, it is also 18 feet thick, but is at 

 the bottom of the coal series, at the height of 302 feet. 

 In Fellows's run, it reaches the height of 418 feet, and 

 its thickness is 48 feet, also below the coal measures. 

 On Elk mountain it reaches, by estimation, to the eleva- 

 tion of 900 feet. 



The difference in elevation at these localities is, of 

 course, materially influenced by the inclination of the 

 strata. In this region, therefore, the conglomerate rock 

 is sometimes placed below and sometimes occurs above 

 the coal measures. Judging from the masses of this 

 rock, which every where cover the highest points, and 

 which are also sometimes seen in situ, I am led to con- 

 clude, that there were originally two deposits of con- 

 glomerates over a great part of this area. There are 

 certainly two at Elk mountain in situ, and three on the 

 hills south of Blossburg, and the opposite or north side 

 of the basin appears to have an original covering of this 

 rock, which is for the most part washed away, leaving 

 its detritus upon the eminences above the coal formation. 

 On the Armenia mountain is a platform of this pudding- 

 stone and gritstone, each bed being about 10 feet thick, 

 overlying the carboniferous beds. 



