PTEROPODA. 
157 
In 1855 Dr. B. F. Shumard described and published Tent, incurvus, from the 
Cape Girardeau limestone, referred by him to the age of the Lower Helderberg 
group ( Geolog. Survey of Missouri, Second Annual Report, p. 195, pi. B, figs. 6 a, b).* 
In 1859 James Hall described Tentaculites elongatus, from the shaly limestone 
of the Lower Helderberg group, and, recognizing that the species occurring in 
the Tentaculite limestone was not the T. ornatus of Sowerby, proposed the 
name T. irregularis, f correcting the same in the explanations of plates, and 
adopting the name T. gyracanthus, given by Eaton in 1832 ( Palaeontology of 
New York, vol. 3, pp. 136, 137, pi. 6, figs. 16-21, 22 and 23). 
In 1863 Prof. J. D. Dana (. Manual of Geology), following Messrs. Mather and 
Vanuxem, cites the T. ornatus as occurring in the Tentaculite limestone at the 
base of the Lower Helderberg group. He also cites the T. scalaris, from the 
Corniferous limestone of New York, following the erroneous determination in 
the Geological Report of the Fourth District. 
In 1865 Messrs. F. B. Meek and H. A. Worthen described three species of 
Tentaculites, viz., T. tenuistriatus, T. Oswegoensis and T. Sterlingensis, from rocks 
of the age of the Hudson River (Cincinnati) group of New York ( Proceed . 
Acad. Nat. Sci. Phila., pp. 254, 255). 
In 1866 Prof. A. Winchell described T. subtilis, from the Hamilton group in 
the State of Michigan ( Report on the Lower Peninsula of Michigan). 
In 1868 Messrs. Meek and Worthen published descriptions with figures of 
T. tenuistriatus, T. Oswegoensis, T. Sterlingensis ( Geolog. Survey of Illinois: Geology 
and Paleontology , vol. 3, pp. 341-343, pi. 4, figs. 6, 7 a, b, and 8). 
In 1874 Mr. S. A. Miller, of Cincinnati, described T. Richmondensis, from 
Lower Silurian strata, of the age of the Hudson River (Cincinnati) group 
(Quarterly Journal of Science, Cincinnati). 
In 1876 Mr. C. A. White described T. Hoyti, from strata of Devonian age 
( Proceed. Acad. Nat. Sci. Phila., p. 34, 1876). 
* This species has the characteristic features of Cornulites in its young state : but its mode of occurrence, 
as described, differs from the ordinary condition of the young forms of that genus. The formation, at the 
locality where the Tentaculites occurs, has more recently been referred to the upper part of the Hudson 
River group, and by S. A. Miller to the Trenton group (Catalogue American Palaeozoic Fossils, p. 142). 
f At that time the author was not acquainted with the work of M. Castelnau. 
