162 ROYAL SOCIETY OF CANADA 
of the fossils made by Prof. H. S. Williams of Yale University some 
years ago, a form resembling Spirifer mesacostalis, Hall, was recognized 
which points to the probable occurrence of this formation. 
In the list of Lower Helderberg fossils given by the writer in Dr. 
Ells’s report above cited four species numbered :—25, 27, 28, 32 re-. 
spectively, were included under the general heading ‘“ Lower Helder- 
berg,” as they formed part and parcel of the same collection. These 
four species ag everyone knows are readily recognizable as Devonian 
species, two of them being characteristic of Hamilton age. They must 
obviously be eliminated from the horizon to which they have been | 
assigned and separated from the species obtained from the main mass 
of the limestones referable to the Lower Helderberg formation, Many 
of the specimens examined are evidently from the brecciated con- 
glomerates and of Devonian age. 
Post-DEVONIAN ERUPTIVES, ETc. 
Hruptives—The precise date or geological epoch when Mount 
Royal, Rougemont, Belœil, Mount Johnson and the St. Helen’s Island 
volcanic agglomerates were formed is not definitely ascertained.  Foras- 
much as these intrusive masses penetrate, cut and considerably alter 
along their line of contact the various strata of the Paleozoic column, 
including Ordovician, Silurian, and, as evidence proves, Devonian 
materials, it must be admitted that these same eruptives must neces- 
sarily be at least of post-Hamilton, and in all probability, of post- 
Devonian age, seeing that the Hamilton fossils noticed are embedded 
in a calcareous matrix which had become cemented and hardened pre- 
vious to the volcanic eruptions taking place which broke the fragments 
and re-cemented them. 
These volcanic hills form conspicuous masses coming through the 
Ordovician plain and consist for the most part of crystalline rocks in- 
cluding nepheline-syenite, or elcelite-syenite, tachyte, dolerite, olivine- 
diabase, breccias, ete. The agglomerates of St. Helen’s Island contain 
fragments of nearly all the geological formations of the district, from 
the Potsdam to the Lower Helderberg and later materials. 
THE Post-TERTIARY OR QUATERNARY. 
The Labrador formation.—As in other portions of the St. Lawrence 
and Ottawa valleys the surface of the underlying rock-formation con- 
stituting the bed-rock is everywhere glaciated and superimposed by a 
more or less extensive sheet of glacial or boulder-clays, “ till,” with sand 
and gravel derived from the various rock formations and their debris 

