α. Blackish grey, fine grained, gneissose granite, composed of quartz, white felspar, and large quantities of fine grains and flakes of hornblende, passing into black mica. The gneissose beds of this granite dip 13° S.E.
β. A red granite, graphic texture, composed of quartz and red felspar, coarse grained.
γ. Syenite, composed of honey-yellow felspar and hornblende, in very large crystals, the felspar passing into red and pink, and the whole rock mass penetrated by veins of the same material, but fine grained. This variety of igneous rock was met with principally at Pemmican Rock, western inlet of Bellot Strait. Large quantities of hornblende are also met with at Levesque Harbor, Bellot Strait, composed of facetted crystals agglutinated together into large masses, forming a crystalline hornblendic gneiss.
10. Pond's Bay, Baffin's Bay, lat. 72° 40' N.—In this locality a quartziferous black mica schist underlies the Silurian limestone, and is interstratified with gneiss and garnetiferous quartz rock, all in beds, inclined 38° W.S.W. (true).
11. Montreal Island, mouth of the Fish River, lat. 67° 45' N.—The granitoid rocks, which everywhere, in the Arctic Archipelago, underlie the Silurian limestone, appear at Montreal Island as a gneiss, composed of bands of felspar (pink) and quartz (¼ inch thick), separated by thin plates composed altogether of black mica; the whole rock exhibiting the phenomena of foliation in a marked degree.
The east side of King William's Island, though composed of Silurian limestone like the rest of the island, is strewed with boulders of black and red micaceous gneiss, like that of Montreal Island, and black metamorphic clay slate, in which the crystals of mica (qu. Ottrelite) are just commencing to be developed. It is probable that the granitoid rocks appear at the surface somewhat to the eastward of this locality.
12. Prince of Wales' Island, west of Peel Sound.—The granitoid rocks extend across Peel Sound into Prince of Wales' Island, in the form of a dark syenite composed of quartz, greenish white felspar passing into yellow, and hornblende. This rock is massive and eruptive at Cape M'Clure, lat. 72° 52' N., and occasionally gneissose, as at lat. 72° 13' N. Between these two points, at lat. 72° 37' N., a limestone bluff occurs containing the characteristic Silurian fossils, and is succeeded at 72° 40' by a ferruginous limestone, bright red, and a few beds of fine red sandstone, like those observed by M'Clintock at Transition Valley, North Somerset. The entire western portion of Prince of Wales' Land is composed of Silurian limestone, which in the extreme west, at Cape Acworth, becomes chalky in character and non-fossiliferous, resembling the peculiar Silurian limestone found on the west side of Boothia Felix.
II.—The Silurian Rocks.
The Silurian rocks of the Arctic Archipelago rest everywhere directly on the granitoid rocks, with a remarkable red sandstone, passing into coarse grit, for their base. This sandstone is succeeded by ferruginous limestone, containing rounded particles of quartz, which rapidly pass into a fine greyish green earthy limestone, abounding in fossils, and occasionally into a chalky limestone, of a cream color, for the most part devoid of fossils. The average dip of the Silurian limestone varies from 0° to 5° N.N.W., and it forms occasionally high cliffs, and occasionally low flat plains, terraced by the action of the ice as the ground rose from beneath the sea. The general appearance of the rocks is similar to the Dudley limestone, and would strike even an observer who was not a geologist. This resemblance to the Upper Silurian beds extends to the structure of the rocks on the large scale. Alternations of hard limestone and soft shale, so characteristic of the Upper Silurian beds of England and America, arranged in horizontal layers, give to the cliffs around Port Leopold the peculiar appearance which has been described by different Polar navigators as "buttress-like," "castellated;" this appearance is produced by the unequal weathering of the cliff, which causes the hard limestone to stand out in bands. Excellent sketches of this remarkable appearance, drawn by Lieutenant Beechey, are figured at page 35 of Parry's First Voyage, 'Hecla' and 'Griper,' 1819-20. The Western side of King William's Island (now, alas! invested with so sad an interest) is a good example of the low terraced form which the limestone rocks assume at times.
The following lists contain the names of the principal fossils brought home by Captain M'Clintock:—