DOVrUNO. 
SILURIAN FOSSILS. 
55 F 
narrow and ral her doep, ohlifjuely transver.se cunstT'iction.s. Between 
these oonsl rietiuns the sipluinele is laterally C(iiii|>ressed and Init slightly 
expanded, while its (lativerse diameter is from two to tin ee tin es as 
great as the dlstanee hetweeii the eonstrictions. 
The .surface makings of these siphuncles consist of fine close set 
longitudinal stria*. 
ITiiny island, Attawapishkat river, l*i‘. K. Bell, 18^6 : three fine 
and rather slender specimen.s. Ekwan liiver, upper rapid : two dis- 
torted fragments. 
'J'he West specimen, from the Attawapishkat rivoi*, which shows ten 
of the ^iphuncular con.striction.s, is three inches and nearly a half in 
length, liy twelve millimelres in di:imeter near the smaller end, and 
twenty-two near the larger. In this speeiim'n the width of thesi- 
phnnele is about twice as great a.s the iHstan<*e lietween two of the 
con.sl.rictions. Tn another e<|Ually .slender but .shorter .speeimen from 
the .same locality, which shows seven siphuncidar const rietion.s, the 
width of the sijihuncle is nt'arly three times .as gnuit fus the distance 
between the con.strictions, at the smaller end ; and <uily twice as great 
at the larger. 
KioiKH'f’ras cunrel/atii ni (Jfall). 
Orlhorrrax fiiiincNiihim, (Hull). LSug. 
OrUi’iri run rnhimnuri , ILsll. ISIK). .N'nt O. co/io;nia»v , .Markliii, 1857. 
Orlhnii nis Sriniimiiiii, O. Jfoiiii, O. linoihflinn, ami O. irrc;iuh(rr, McC'lie.‘i)iey. 
isill ; ti*.stf Hull. 
Oiiliwrrox Wwirl irorlli t, .Met 'lii'uiii'y, 18(15; icstc Hull. 
Orlliin’t nix Ciiilmiix, I lillinj's. I.SSd. 
OrthiH'i nix <iw/u/ii(init, Hull. 18(17. Hut nut O. u/i'/»/uOo;(, Walileiihorp. 1821. 
Orthiii-rnix rinjiitinn, Hall. 18(17. Not O vinjutvm, .‘^owerhy. IH.'ll). 
Orthori rnx xiihniiird/nluiit. Hall. 1.877. 
Oi'llwcrnix nriix, Hall. 1877. 
1‘^ksvan river: portage* road at fall.s, two fragmentary specimens, the 
largest less than two inches in h'ligth; ami middle rapid, two .similar 
fragments j all of whivh .seem to be referable tf) this species. Ivich of 
the.so s[)ecimens is a portion of a )ongi('one orthoceratite, with a cir- 
cular traiisver.se .si’ction, a central or nearly central siphunch^, and 
marked with nai*ro\v longitudinal ridgij.s, separated by wider grooves 
or intervals, with minute, clo.se-set, transverse, rai.sed linos between 
them. .Specimens with similar external cbaractors liave been found 
in the Niagara and Guelph formations at three localities in Ontario 
and Quebec. These are the Orthoceras Cadmus, of Billings, from 
