THE DEVONIAN OF CAPE BRETON—GILPIN. 383 
bonized, plants, cordaites, ferns, calamites, and sphenophyllum 
are met. Argillites of varying degrees of hardness are found, 
with green, black, and red colors, and are frequently nacreous. 
The conglomerates are red and greenish, and compact; the peb- 
bles being quartzite, with sandstone and felsite, and they are 
frequently banded with sandstone. 
Limestones are met at many points and they differ from those 
of the carboniferous, in being in all cases highly altered, in places 
approaching marble in texture. The limestone seen at many 
points between St. Peter’s and Macnab’s cove is bluish and grey, 
esmpact, crystalline, concretionary or slatey. Galena is some- 
times observed in it, and layers of chloritic matter. At Robert- 
son’s cove the limestone contains conularia, strephtorynchus, and 
stems of plants and other organic forms. It contains veins and 
nests of crystalline spar, hematite, etc. Another limetone near 
MacNab’s cove is described as blackish, bluish, grey, yellow 
weathering, dressed with hematite, veined with calespar, with 
cone in cone concretions, and holding dark purple fluorspar. 
In the northern part of the district these measures are rather 
more compact and altered than near the shore. At numerous 
points they have their joints filled with calespar. These mea- 
sures are cut by numerous masses and ridges of trap and diorite. 
The St. Peter’s Canal is excavated in a mass of greenish, grey 
and yellow mixtures of hornblende and felspar, etc. Dykes of 
coarse greenish diorite are met, slightly altering in their immedi- 
ate vicinity the sandstones and grits they intersect. Black, 
bluish and greenish trap passing into felsite or diorite occurs at 
Alex Island. Its cavities contain hematite, calespar, chlorite 
and zeolites. 
These strata cut off by the sea emerge again, and as already 
noted, occupy nearly all the island of Arichat. 
Mr. Fletcher, during the seasons of 1878 and 1879, continued 
the work of tracing the geological formations of Richmond and 
Inverness Counties. He, however, raises a question if part of 
the beds on this Island may not be older, and refers to the opinion 
of Sir William Dawson, who is inclined, on specimens of a species 
of Rhynchonella Se, by him at Rocky Bay, near Arichat, to 
