J. W. Salter on Fossils from the Ottawa River. 229 
stones, the lowest bed of which is composed of a collection of 
great boulders and blocks of sandstone, some of them nine feet in 
diameter, that were lying immediately on the strata from which 
they were derived when they became covered up, and in which 
. great cracks and worn fissures are filled with the calcareous depo- 
sit that envelops the whole. 'The sandstones being without dis- 
covered fossils, it is not easy to determine their age; but the 
limestones by their organic contents are distinctly shown to be- 
long to the Upper Silurian epoch. The Lower Silurian deposits, 
unless the non-fossiliferous sandstones be a member of the group, 
a8 many specimens as have been brought remain in the province 
from other parts, while great additions, it is hoped, will annually 
be made to them. 
_ 2 Note on the Fossils above mentioned, from the Ottawa River. 
By J. W. Savrer, F.G.S., A.L.S. 
Lower Silurian.—The fossils from the southeast end of Allu- 
mette Islands, on the Ottawa River, are the only Lower Silurian 
ossils yet examined of Mr. Logan’s large collections, and they 
bear out well the opinion he has expressed, that in some parts of 
Canada but one calcareous group can_be distinguished between 
the Potsdam sandstone below, and the Hudson River group above, 
ing i in wi rated “’T'renton limestone” o 
New York, but possessing also many of the fossils characteristic 
of the lower limestones which in that country have received sepa- 
Tate names. ‘ 
