Suburban Geology of Richmond, Indiana. 299 



posing, tarnish the surface of the stone. I have also several times 

 discovered in this building stone, as it is emphatically called, lit- 

 tle cavities filled with a black, waxy matter, which I suppose to 

 be bitumen. 



In this immediate neighborhood, this rock presents itself in 

 thin, lenticular layers. It furnishes our best lime, and is prefer- 

 red for " metaling"* the national road, but is rarely used in build- 

 ing. The well known fitness of this rock to form water-falls, is 

 prettily exhibited here in several instances. These cascades 

 have, from their resemblance in miniature to the Niagara Falls, 

 been called by Dr. Locke niagarets. To my eye, the similarity 

 is quite striking. At one of these water-falls, I have found por- 

 tions of this limestone with dark brown stains of bitumen, the 

 odor of that substance being very strong. 



Fossils. — In this formation fossils are seldom obtained entire ; 

 they are mostly calcareous, but sometimes siliceous. Imperfect 

 as they are, I have been able to make out the following genera: 

 among the zoophytes, a species of Gorgonia ; two species of 

 Retepora; a small, invariably black Cyathophyllum, and a lar- 

 ger, always light-colored species; Tubipora catenulata; Cate- 

 nipora labyrinthica ; an Eschara different from that of the blue 

 limestone ; Calamopora Gothlandica, and another species. 



Of bivalves, I have discovered the Atrypa affinis, Strophomena 

 rugosa, and three other species, two of which resemble $. del- 

 toidea and $. alternata ; Orlhis testudinaria, and apparently two 

 other species ; and in one locality the rock is almost exclusively 

 composed of large and fine Pentamera, some of them being sev- 

 eral inches in diameter. 



Crinoideans are much more common in this formation than in 

 the rocks below ; and of the crustaceans, Ave have the Calymene 

 senaria. 



These are not all the fossils afforded by our cliff rock, but they 

 are, I think, the principal kinds. Among the unnoticed species 

 is a smooth, hemispherical and concave body, half an inch in 

 diameter, with a folded margin. Another fossil, per- rig. it. 

 haps, deserves a figure : the appearance of this film M 

 on the rock is well calculated to give the observer an 

 impression of its being a winged seed. I have al- 



* The term "metal" is in general use among engineers to designate the frag- 

 ments of stone used as the foundation or superstructure of roads. — Eds. 



