Maryland Geological Survey 385 



On the Pea Eidge Eoad li^ miles south of Avilton, opposite the house 

 of Mr. John Robinson, is an interesting exposure of a massive con- 

 glomerate rock in place and this is the only known locality in northern 

 Garrett County in which this occurs. It becomes, therefore, a place of con- 

 siderable interest. The ledge is shown by the side of the highway, just 

 west of the house, where it is dipping at a rate of from 34° to 39° S., 

 60° E. A little lower are numerous large blocks of the conglomerate 

 which on long exposure have weathered to a very light gray color. 

 The rock passes from a quite coarse pebble conglomerate through a 

 grit into a coarse quartzose sandstone. In fact much of the rock 

 really varies from a grit to a fine pebbled conglomerate; but is almost 

 entirely composed of the coarse material like a fine pebble deposit on a 

 recent sea beach. The color on recent unweathered fractures of the rock 

 is rather a rusty brown; but the outside of the blocks on long exposui-e 

 bleach to a very light gray or almost white. Some of the rock shows 

 layers of pebbles through a coarse sandstone, while some of it is a 

 sandstone containing an occasional pebble. The stratum by the roadside 

 is mainly a sandstone varying to a grit and shows a thickness of at least 

 3 feet. One block of the conglomerate on the stone crop had a thickness 

 of 20 inches. There are in parts of the rock quite large, flat, white quartz 

 pebbles which have broken with a smooth fracture on the joint surfaces. 

 No jasper pebbles, however, were found and in that particular it does 

 not agree with the Avilton conglomerate. It does, however, resemble quite 

 closely the conglomerate in the upper part of the Jennings formation in 

 Jennings Eun. This ledge is on the eastern side of the anticlinal fold 

 and in the line of the strike about N. 35° E. At the second turn of the 

 road to the northeast of ]\Ir. Robinson's are numerous loose blocks of the 

 conglomerate. 



Before reaching the first road turning east there are outcrops of green- 

 ish Jennings shales which are dipping sharply eastward, and in blocks 

 of loose greenish sandstone on top of the ridge near the corner are 

 specimens of pelecypods. On this eastern road some distance below 

 the summit of the hill is a zone of greenish to greenish-gray micaceous 

 sandstone and olive argillaceous shale in which is a yellowish-gray con- 

 25 



