Till. — Contributions to Invertebrate Palaeontology. 



BY R. p. WHITFIELD. 



Read October 13, 1S90. 



I. Descriptions of Fossils from the Pal-eozoic Rocks of Ohio. 



la submitting; for publication the following descriptions and 

 observations of Ohio fossils I feel it due to m3rself to account for 

 its detached and apparently incomplete character, to state that this 

 arises from the fact, that it is essentially a report on certain groups 

 of fossils submitted to me, partially for the purpose of ascertaining 

 their horizons or for determining their relations to other beds the 

 horizons of which were supposed to be already known. In the 

 effort to carry out these objects, besides the specimens and informa- 

 tion which I have received from Dr. Newberr}^, I have been aided 

 by the loan of specimens and by other assistance from President 

 Edward Orton, of the Ohio State University, and by the Hyatt 

 Brothers, students in that institution, who have furnished me much 

 information in regard to localities and horizons of different species, 

 as well as lists of those known to occur in particular beds in the 

 vicinity of Columbus; and also with specimens from their private 

 collections. To the late Rev. E B. Andrews, of Lancaster, Ohio, 

 I am also indebted for the use of many of the specimens illustrating 

 the Alaxville limestones 



The fossils illustrated on Plate Y, represent forms that are found 

 exclusively in the hydraulic cement beds of the State, which repre- 

 sent the lower part of the Lower Helderberg and Waterlime groups 

 of New York. The character of the fossils is such that no com- 

 ments are necessary in regard to the horizon they represent. Plates 

 YI to X inclusive, contain figures of species from the limestones 

 below the horizon known as the "Bone bed" in the vicinity of 

 Columbus, Ohio, and are to a great extent illustrations of hereto- 

 fore undescribed forms. The forms represented on Plate XI are, 

 with one exception, known species; they represent horizons not 

 Annals N. Y. Acad. Sci., V, Dec. 1890.— 34 



