192 
PALAEONTOLOGY OF NEW YORK. 
Kjerulf, F. A. Biemer and others, in ignorance of the preexisting name of 
Hyolithes. 
In 1847 M. Barrande proposed the name Pugiunculus, and was followed by 
Sandberger and others. 
In 1848 Mr. Salter described Tlieca anccps, from the Upper Silurian of the 
Malvern Hills (Memoirs of the Geol. Survey, vol. 2, pp. 255-355, pi. 14, fig. 17). 
In 1850 Prof. d’Orbigny proposed the generic name of Vaginella, which 
includes fossils of the genus Theca=Hyolithes as Avell as other forms. 
In 1857 the Chevalier Eichwald reproduced the generic description of his 
genus Hyolithes, making reclamation of priority for the name ( Beitr ., in Bull. 
Soc. Imp. des Nat. de Moscou, p. 146). 
In 1864 Prof. Ludwig included these forms under Cleodora, and Salter, in 
1866, under the genera Clidotheca and Centrotiieca in part. 
The American species of this genus have been described in the following order: 
In 1847 the writer described Theca triangularis (Pal. N. Y., vol. 1), which 
was subsequently re-described by Billings (1871) as Hyolithes Americanus; the 
name triangularis having been preoccupied by Portlock in 1843. 
In 1851 I indicated the occurrence of similar bodies at the base of the 
Calciferous sandstone on the Escanaba river (Foster and Whitney's Report on the 
Lake Superior Land District). These fossils are probably identical with those 
subsequently described as Theca primordialis. 
In 1860 I described Pugiunculus? (Theca) aculeata,, from the Goniatite beds of 
Bockford, Indiana; in ^861 Theca primordialis, from the Potsdam sandstone of 
the Mississippi Valley, and in 1862 Theca parviusculus, from the Hudson Biver 
group, and Theca ligea, from the Upper Ilelderberg group. 
In 1861 Meek and Hayden described Theca gregaria, from the Potsdam sand¬ 
stone of the Big Horn mountain (Proceedings Phila. Acad. Nat. Sci.). 
In 1871 E. Billings described Hyolithes Americanus (= Theca triangularis, 
Hall, 1847), and in 1874 H. communis, H. princeps and H. excellens; all from the 
Potsdam group. 
In 1872 Mr. Ford described Hyolithes impar, and in 1873 II. Emmonsi, from 
the Potsdam group. 
