446 GEOLOGY OF OHIO. 



southern boundary line to the vicinity of Rock Mills. To keep the con- 

 tinuity of strata, as we proceed in our investigations, we shift the scene 

 from Rattlesnake to Paint Creek. 



The next outcrop ascending this stream, above the striated rock in the 

 vicinity of Smart's Mill, in Ross county, is above the bed of the creek 

 and one or two miles up stream from the last locality on the farm of Mr. 

 Evan James. Here, we observe, a marked change has taken place in 

 the litholbgical character of the bedded rock. I had no instrumental 

 equipment which would enable me to ascertain whether or not this stone 

 was conformable in dip with that of the last exposure. A considerable 

 difierence in altitude existed between the two exposures, but the inter- 

 vening formations were not visible. The stone at James' is a limestone, 

 light in color, and fine grained, a good quality of stone for building pur- 

 poses. The quarry was but little worked where the building stone had 

 been procured, but a short distance further up the etream, the strata near 

 the creek are very thin, often not more than one-half an inch thick and 

 none more than two inches thick, nearly white in color, and show finely 

 sun and water cracks. These marks are delicate but distinct, and roughen 

 the surface but little. They seem to have been formed on the beach of 

 a shallow, quiet water. The stone is fine in texture And soft to the touch. 

 These strata are traced along the creek for about two miles, getting some- 

 what thicker in the upper part of Rogers' quarry. In no part of this 

 distance were any organic remains discovered, but on the Washington 

 and Greenfield turnpike, fifty or more feet higher on the horizon and 

 about west from the point of first appearance of the bedded rock in the 

 creek, in the ditch by the road side, occur strata which show clearly 

 marked indications of a lamellibranch mollusc less than a quarter of an 

 inch in its longest measurement, also very distinct and beautiful fucoidal 

 impressions. The fractures showed delicate markings of dendrites. This 

 is perhaps the same stone which occurs west of this locality at Mrs. Pos- 

 ter's on Walnut Creek, and has a local reputation as a fire-stone. 



Another and more massive exposure occurs two miles above Rogers', 

 a harder stone than any found below on Paint, and in some respects re- 

 minded me of the Clinton. 



The locality of Rock Mills presents more points of interest to the geol- 

 ogist than any other in Fayette county. Below is a section of all the 

 strata visible in Dhis vicinity. 



FKET. 



Yellow clay, seen on ridge east of the creek 6 



Blue clay, " " " 5 



Shale or slate, " " " 10 



