Stevenson.] AJ& [Au<i. 15, 



Between Bedstone Greek and Pittsburgh, The benches axe handsomely 

 shown on both sides of the river below the mouth of Redstone creek, 

 which enters the river at Brownsville, 50 miles above Pittsburgh. At 

 Belvernon, near the northern line of Fayette county, the deposit on the 

 third bench has been opened to procure glass-sand ; and at present two ex- 

 cavations are worked on the opposite side of the river. At the upper one 

 of these the following detailed section was obtained : 



1. Alternations of fireclay, gravel and coarse sand, with frag- 



ments of varying size ; the whole containing much carbon- 

 aceous matter in streaks, mostly broken coal ; very ferrugi- 

 nous toward the base 12 to 10 ft. 



2. Sand, fine and angular, excellent for manufacture of fine win- 



dow and mirror glass ; containing thin, irregular layers of 

 blue plastic clay, with occasional layers of conglomerate 

 cemented by oxide of iron ; contains also numerous rounded 

 fragments of rock, some of them very large ; the pebbles are 

 of limestone, sandstone, and carboniferous conglomerate 16 to 22 ft. 



3. Coarse sand and gravel, with many small rounded fragments ; 



much carbonaceous matter, coal, and imperfect lignite ; oc- 

 casionally yields large fragments of trees. This is often a 

 ferruginous conglomerate 2 ft. 



4. Ferruginous sand, frequently conglomerate ; contains some 



transported fragments of considerable size 2 to 4 ft. 



5. Blue plastic clay to 4 ft. 



6. Blue laminated shale of the lower barren series. 



The plastic clay, No. 5, is evidently derived from the underlying shale 

 on which the deposit rests. The section shown in the other excavation is : 



1. Clay, containing rounded fragments, lumps of coal, etc 10 ft. 



2. Dark sand used for moulding 7 ft. 



3. White sand, used in making glass 7 ft. 



4. Sandy and clayey material, containing rounded fragments 



and lumps of iron ore 1 ft. 



5. Dark sand 4 ft. 



As these excavations are barely half a mile apart, they show the extreme 



irregularity of the deposit, which is from 40 to 45 feet thick at the upper 

 excavation, while at the lower one it rarely exceeds 35 feet. 



At, Monongahela city, the third and fifth of the Stewartstown benches 

 are at 190 and 320 feet above low water mark ; above these are the sixth 

 and eighth at 1110 and 1190 feet above tide. Between the third and fifth 

 there is an ill-defined bench at 290 feet above low water, which is distinct 

 further down the stream, for a terrace, holding that place, is reported from 

 Peter's creek and Thompson's run. The third bench, also, is well denned 

 down the river, being that along which the Pennsylvania Railroad runs 

 from just below Braddocksneld almost to Pittsburgh. 



The lowest bench at Monongahela city is at 40 feet above the river or at 

 750 (Vet above tide. The Baltimore and Ohio Railroad runs along this 



