232 J. W. Salter on Fossils from the Ottawa River. 
North Welsh specimens of this fine shell, which measures two 
inches across, I can find only trivial variations. It does not re 
quire a new specific name, having been figured from an imperfect 
specimen, as Atrypa transversa, by Portlock. It is interesting to 
find this species (which of course, as a Pteropod, had ready means 
of migration) in the two countries. There are but few other 
species identical with those of Great Britain, but I think I recog- 
nise T'urbo trochleatus, and perhaps 7’. iritorquatus, M‘Coy, as 
common to the two regions. = 
Of the Cephalopoda, the remarkable two-edged Orthoceras, 
called Gonioceras anceps by Hall, is a Black River limestone 
species. Cyrtoceras is common, both smooth and. ornamented ; 
C. annulatum and C. lamellosum, the same with those of Tren- 
ton; Orthoceras arcuo-liratum, bilineatum, and laqueatum, Hall, 
are Trenton limestone species ; and lastly, there are two species 
of Ormoceras, Stokes, the larger of which is in all probability 0. 
tenufilum, Hall, aspecies both of the Black River and Trenton beds. 
Schizocrinus nodosus, Hall, of the ‘Trenton limestone, is the 
_ common crinoid; its stems are very characteristic. 
Among the corals, one or two species of Streptolasma, appa- 
rently the same as those of New York, and the branched varieties 
of Flavosites lycoperdon, accompany those before mentioned ; an 
we may-here notice the Receptaculites, already described by Hall, 
but not I think identical with R. Neptuni of Europe. ‘The tine 
series brought home by Mr. Logan shows all the structural cha- 
racters ;—the circular expanded form and cup-like centre,—the 
surface composed of rhomboidal plates, which cohere by lateral 
processes, and which are the flattened ends of separate and equi- 
distant columns. Unfortunately the entire structure is replace 
by cycloidal silex, but perhaps it will, by eareful polishing, enable 
us to see if it be really a coral, somewhat of the character of the 
Tubiporide. 
To crown all these are slabs full of the large Asaphus ( Isote- 
lus) gigas, the characteristic trilobite of the Trenton rocks. 
Upper Silurian Rocks.—Ascending the Ottawa to the head of 
Lake Temiscamang and so crossing the granitic axis of Canada, 
the first fossiliferous rock that presents itself is of a totally difier- 
ent character to that last described, as stated by Mr. Logan in bis 
Report of Progress for 1845. : 
This limestone is weathered like the last; its siliceous fossils 
also stand out in bold relief; and one of the most common 1s the 
characteristic crinoid of the Trenton limestone, Schizocrinus 20 
dosus, at least I believe Lam correct in this reference. But along 
with this are abundance of Favosites gothlandica, Stromatopor 
siriatella, Cyathophyllum, a Heliolites (Porites), with small 
tubes; Syringopora (Harmodites) with Halysites catenulatus 
