130 Cincinnati Society of Natural History. 



feet above known exposures of the Hudson River Group. Last summer, 

 Mr. Braun and I collected, near Osgood, in Ripley County, Indiana, 

 within less than thirty feet of the Hudson River Group (top of the 

 Cincinnati Group) several species of these large Cystideans.^ with many 

 roots and columns, • As soon as opportunity occurs for illustrating 

 these, more of them will be described. Later, Prof. A. G. Wetherby 

 collected, near Osgood, several species in the same range, and within 

 30 feet of the Lower Silurian rocks. We are not informed as to the 

 place where Dr. Washburn found his specimen, farther than it was 

 some distance below the range of the Waldron beds. The plates of 

 Cystideans^ from the same range of rocks, at Dayton, Ohio, have been 

 known for many years. 



. Associated with these Tlolocystites^ in Ripley County, Indiana, I 

 collected Lichenalia concentrica.^ Calymene niagarensis^ Orthoceras 

 annulatam, Atrypa reticularis, having the same characters as the 

 Waldron specimens, and other fossils of the Niagara Group. I have 

 been unable to find any indications of the existence of the JMedina or 

 Clinton Group, at au}^ of the exposures examined, and from the ob- 

 servations made, and fossils collected, am fully convinced that the Ni- 

 agara Group rests directly upon the Hudson River Group of rocks, all 

 the way from Dayton, Ohio, in the meandering course of the exposure 

 across the south-eastern part of the State of Indiana, to the Ohio river. 

 It is true, that I have not traced out the line of junction of these two 

 Groups the whole distance, nor the greater part thereof, but I have seen 

 exposures, where the Groups come together, and have collected fossils 

 in the rocks of both Groups, at a great many places near the line of 

 junction. Moreover, the rocks have never suffered much disturbance, 

 and have a very uniform westerly and north-westerl}^ dip. In short, I 

 have the utmost confidence in the correctness of the view expressed, 

 notwithstanding the statement, which has been made, to the effect, that 

 the Clinton Group intervenes. Certainly no one will have any doubt 

 about the age of the rocks in which these fossils were collected. 



HoLOCYSTiTES BRAUNi, u. sp. (Plate v., fig. 1, natural size.) 

 The species is founded upon a single specimen, half of which is 

 buried in a slab. 



The body is elongate-subovatc, apparently sliglitly constricted imme- 

 diately above the junction with the column. The part of the column 

 preserved is very large, and there are some appearances that render it 

 possible that it is all preserved; that the species was sessile and rested 

 close upon its support; and that the apparent constriction is caused b}^ 

 the expanding support or flange. 



The basal (?) plates are, in part, anchylosed, which prevents a correct 



