296 Dr. John T. Plummer on the 



does not contain all that are found in other localities of the blue 

 limestone in the west, is certain. Perhaps we may safely look 

 upon our strata as constituting the summit of this formation ; 

 this would lead us to anticipate some difference in its fossil con- 

 tents from the lower strata, which appear at Cincinnati and other 

 places to the south of us- Hence, as we go in that direction, 

 we find an increase of crinoideans ; other species, and indeed 

 genera of trilobites, as Cryptolithus tesselatus; one or more spe- 

 cies of Apocrinites ; much larger bivalves of the same genera as 

 ours, with other similar variations. 



Diluvial Scratches. — A few months ago, while collecting spe- 

 cimens in natural history two miles north of the town, my atten- 

 tion was arrested by the flat, smooth, and whitened surface of 

 some quarried rocks which had been thrown together in a heap. 

 On close examination, I satisfied myself that art had not wrought 

 this appearance, but that the rocks had been polished and 

 marked with parallel lines by some great natural force. Deeply 

 interested in the discovery, I looked around to find some of the 

 rock in place ; but I soon ascertained that the grooved stratum 

 could not be seen without the aid of spade and mattock. The 

 stream on which it occurs, and the locality, may be seen by re- 

 ference to fig. 1. The quarry not having been used for some 

 time, the oozy bank above it had slidden down so as to cover 

 the stratum to a considerable depth. 



As soon as possible after the discovery, I returned to the spot 

 with the necessary implements and a person to assist me. By 

 diligent digging and shoveling, we exposed the uppermost and 

 desired surface in a number of places, to a sufficient extent to 

 ascertain accurately the character of the grooves and their direc- 

 tion. The grated stratum was covered by an exceedingly dense 

 clay, which required the strongest efforts with the mattock to 

 penetrate and detach it from the rock. With care we separated 

 several large flakes of the clay, and on examining the under 

 surface, we found it beautifully impressed by the rectilinear en- 

 gravings of the stone on which it had rested. Above this indu- 

 rated clay, lie gravel, sand, clay, and soil, to the depth of fifteen 



feet. The stream runs by the quarry, perhaps thirty feet below 

 the level of it. 



On taking the direction of the lines with a compass, we found 

 them to run S. 20° W. In several places water trickles over the 







