﻿Remarks on Markings on Rocks — Cincinnati Group. 161 



One species, 0. moniliformis was described and figured. The author 

 remarks that it resembles ''somewhat the impression made by a small col- 

 umn of Heterocrinus simplex, though longer beaded." It was supposed to 

 have been made by a Gasteropod, though there can now be little doubt 

 but that it was really made by a crinoid stem. 



On slabs of rock bearing impressions referable to this species, there 

 are often found curious waved and curved lines running parallel with each 

 other, and sometimes covering considerable spaces of the rock. Occas- 

 ionally at one end of the chain will be noticed a widening out. Here is 

 the first indication of the source of the mark. It has been made by the 

 stem of a crinoid, which, fastened at one end, and resting on the mud, has 

 been moved to and fro by the water, and has thus left a trail. Each one 

 of the divisions of the column has scooped out a depression. The further 

 from the attached end, the wider will be the mark. The interruptions, in 

 some instances, indicate that the stem has only at times touched the mud 

 surface, while at other times the marks having once been made were de- 

 stroyed by currents of water. 



On the slabs containing these marks, fragments of crinoid stems are 

 sometimes found. Often the marks imitate the stem so exactly that it re- 

 quires close inspection to see their true character. But the real origin of 

 the marks is conclusively shown in a specimen found near Cincinnati and 

 in one found in the upper part of the Group (Clinton county, O.) by Mr. 

 U. P. James. r l 'his last specimen is six or eight inches long, of very com- 

 pact limestone, having on it one of these trails. The trail is about three 

 inches wide at one end, and the center is scooped out into a hollow about 

 half an inch deep. At the lower end is the crinoid stem, or part of it, 

 which made the mark. The hollow is marked with curved parallel lines, 

 each line as far from the next one as are the joints of the column. It is 

 quite evident that the hollow has been formed by the sweeping to and fro 

 of the stem, and the ridges indicate the situation of the joints. 



Another ot the ill-defined and obscure fossils which have been 

 described, has received the name of 



Walcottia, Miller & Dyer. 



The genus was described in the Journal of the Cincinnati Society of 

 Natural History, Vol. I, page 39. It was considered to be an annelid. 

 It consists of "long, tapering, rugose, flexuous bodies, worm-like in form." 

 "The fossils taper to a point at one end, and are enlarged at the other, or 

 present the appearance of suddenly bending down and entering the rock." 



