100 



portion of the body chamber about an inch and a half long, but there is 

 a piece missing between them, which, from the rate of tapering, is 

 estimated at nearly two inches in length. Allowing two inches for the 

 missing piece, the specimen, which even then is imperfect at both ends, 

 could scarcely have been much less than eight inches and a half long. 

 It has a considerable portion of the test preserved, especially at the 

 smaller end, and the position of the siphuncle is clearly seen in two 

 nearly transverse fractures. The surface markings consist of narrow 

 and continuous longitudinal ridges, separated by rather wide intervals, 

 and by numerous transverse raised lines between the ridges. The 

 siphuncle is very nearly central. 



In the Twentieth Regent's Report, Hall says that his 0. angulatum 

 "is probably the species described by Mr. McChesney, in a paper 

 published in 1861, under the names 0. Scammoni, 0. Hoyii, 0. lineolatum, 

 0. irregulare, 0. Woodworthi. The last one figured is a fragment less 

 than an inch in length. A gutta-percha cast sent by Prof. Winchell 

 under the name 0. Scammoni, corresponds very well with specimens 

 referred by me to 0. aiigulatmn. Should the species prove distinct from 

 the European one, we may select a name from among those above cited." 

 In a foot note to page 412 of the revised edition of that Report, he says 

 also, in effect, that 0. angulatum, Hall, 0. columnare, Hall, 0. Scammoni, 

 McChesney, and 0. Cadmus, Billings, are all probably the same species, 

 and in the explanntion of one of the figures of 0. angulatum, in the same 

 Report, it is stated that the character of its surface " is precisely like 

 that of 0. cancellatum., Hall, from the Niagara group of New York, and 

 differs in no essential particular from the minute surface markings of 

 0. colum,nare.'' 



At different times no less than ten names have been given to this 

 species, but, of these, 0. Scam,m,oni, McChesney, is here provisionally re- 

 tained on the ground that it appears to be the first that is nOt pre-occupied. 

 Mr. Foord's figures of English and Swedish specimens of 0. angulatum,, 

 Wahlenberg, on page 71 of the first part of his catalogue of the Fossil 

 Cephalopoda of the British Museum, represent shells that are distinctly 

 curved, with sub marginal siphuncles, but his description of 0. canali- 

 culatum, Sowerby, applies remarkably well to the large Elora specimen 

 here referred to 0. Scammoni. 



Orthocehas Darwini, Billings. 



Orthoceras Dariviid, Billings 1862. Geol. Surv. Canada, Pal. Foss., vol. 



I., p. 161. 

 Gyrtoeeras Myrice, Hall and Whitfield. , ,1875. Geol. Surv. Ohio, vol. II., pt. 2, p. 



149, pi. 8, fig. 9. 



