ii8 The Ottawa Naturalist. [October 



however, quotes Inochus undatus as a manuscript name of Conrad's, 

 who was then the State Paljeontolog^ist, and states that " this fossil 

 is known to me only as occurring at Watertown, Jefferson Count}', in 

 the Black-river (or ' seven foot tier'' of) limestone, bein^ unknown in 

 any hig-her position." 



1857. About this date a few specimens from the Black River limestone at 

 Lorette and other localities in the Province of Quebec, were identified 

 with Lituites undatus by E. Billings. In this year Professor E. J. 

 Chapman expressed the opinion that these and other specimens ot L. 

 undatui, should be referred to the genus Cryptoceras, d'Orbigny, but 

 it has since been shown that this name is preoccupied. 



1863. In the Geologj' of Canada, page 156, Lituitis ti7idatus \s recorded as 

 occurring in the Black River limestone on the St. Charles River, at 

 St. Ambroise, four miles north of Lorette. 



1883. Professor A. Hyatt, in his "Clenera of Fossil Brachiopoda" published 



in the twenty-second volume of Proceedings of the Boston Society ot 

 Natural History, refers all the specimens thai Hall figured as L. 

 undatus to Conrad's genus Trocholites, but has since abandoned this 

 conclusion. The siphuncle of Trocholites, it may be mentioned, is 

 either central or near the dorsum. In this paper, also, H^att pro- 

 poses and briefly characterizes the genus Plectoceras. 



1884. Professor Gustav Lindstrom, in his memoir on the Silurian Gastropoda 



and Pteropoda of Gotland, says that the generic name Itiachus 

 Hisinger (1838) cannot be used for a mollusk, as it is pre-occupied in 

 Crustacea, and that it "consisted of three species, of which one, /. 

 sulcatus, is a Pleurototnaria, I. angulatus is an Oriostoma, and /. 

 costatns a cephalopodous shell, probably a Trochoceras.^' 



1891. Dr. A, H. Foord, in the second part of his " Catalogue of the Fossil 

 Cephalopoda in the British Museum," claims that Hall has figured 

 more than one species under the name Lituites undatus, and describes 

 one of these as Trochoceras Halli. The types of Dr. Foord's species 

 are two apparently rather small specimens, that do not show the 

 shape or position of the siphuncle, from the Black River limestone at 

 Lorette ; but these are stated to be the same as the specimen of Z. 

 undatus figured by Hall on Plate XIII, figs, i and \a (cast. excl. ) of 

 the first volume of the Palaeontology of New York. 



1894. Hyatt, in his " Phylogeny of an Acquired Characteristia," published 

 in the thirty-second volume of the Proceedings of the American Philo- 

 sophical Society, refers all the specimens that Hall figures as Lituites 

 undatus to Schroeder's genus Eurystomites, but says that *' there are 

 several species usually placed under the name Lituites undatus.'''' He 

 makes no mention of Foord's Trochoceras Halli in this connection, but 

 gives the name Plectoceras obscuruni to a supposed new species, 

 which he does not figure, and of which all that he says is that it 

 "occurs in the Black River fauna in New York and is quite com- 



