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 Sowerbt, proposed the 

 name T. irregularis,^ correcting the same in the explanations of plates, and 

 adopting the name T. gyracanthus, given by Eaton in 1832 (Paleontology 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. \\ inchell described T. subtilis, from the Hamilton group in 

 the State of Michigan (Report cm 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 Cornolitbs in its young state : but its mode of occurrence, 

 Mibed, iMHim fc«B the ordinary condition of the young forms of that genus. The formation, at the 

 locality where the Tkmactutks occurs, has more recently been referred to the upper part of the Hudson 

 River group, and by 9. A. Mim.kk to the Trenton group (Catalogue American Palwoioie Fossils, p. 142). 



t At that time the author was not acquainted with the work of M. Castelnau. 



