The crystalline rocks appear to form the southwest coast of Baffin island for some distance beyond King cape on the east side of Fox channel, when they give place to a wide area of low lands extending nearly to the head of Fox channel, where the crystalline rocks again form the higher lands to the north and east of Fury and Hecla strait.
On the late voyage of the Neptune the rocks of the east side of Baffin island were examined at Ponds inlet, on the islands on both sides of Cumberland gulf, and at Cape Haven and Frenchmans cove on Cyrus Field bay. In other places the ship passed sufficiently near the shores to allow of a good idea being formed of the rocks by the aid of powerful glasses.
Examinations of the rocks were made at Button point, the southeast part of Bylot island, on the north side of the entrance to Ponds inlet; also in the vicinity of Salmon river some thirty miles up the inlet and on its south side, and at Erik harbour on the same side near the mouth of the inlet. At all these places typical Laurentian gneisses and schists were obtained. Among the specimens brought home from these localities is a light-coloured coarse-grained augen-gneiss consisting largely of white and pink feldspar, with thin bands of biotite and little quartz. Another seeming variety of this rock is a well-banded fine-grained mica-gneiss composed of pink and white bands of feldspar separated by thin bands of mica. Associated with these are bands of very quartzose gneiss varying in colour from light to dark from the varying proportions of mica present. These gneisses are usually found containing a considerable number of dark-red garnets; and they probably represent a metamorphic series. A fine to medium-grained rock, usually somewhat foliated, and composed largely of dark-red feldspar with much mica, little hornblende and quartz, cuts the foregoing gneisses, and probably was the granite which altered them by intrusion to their present state. The basic intrusive rocks are represented by dark-green diabase, or its alteration products, dark hornblendic and chloritic schists and gneisses. Taken as a whole, this series of specimens would answer for any of the typical Laurentian regions of northern Canada.
At Cumberland gulf the rocks were examined at Kaxodluin on the south shore, some twenty miles from Blacklead station; also at Blacklead and at Kekerten islands. At Kaxodliun light and dark-coloured mica schists and gneisses were found, cut by a light-pink mica-granite-gneiss. The dark schistose rocks were decomposed near the surface, and contained a considerable amount of disseminated pyrite. Between this place and Blacklead the ship followed the shore-line closely, so that the prevailing dark, rusty gneisses were distinctly seen.
The most abundant rock on Blacklead island is a coarse-grained, pink mica-granite-gneiss, containing large feldspar crystals. This cuts, and is foliated with, coarse, dark mica-schists, and finer-grained lighter-coloured quartzose gneisses. Some of the dark schists contain flakes of graphite, and this mineral is said to be abundant in places on the islands and shores of the gulf farther to the westward, where attempts have been made to work some of the mica and graphite deposits, without much success.
At Kekerten similar gneisses are found, along with large masses of diabase and greenstone, somewhat decomposed near the surface, where it weathers reddish.
At Frenchman cove at the head of Cyrus Field bay, the prevailing rock is a coarse-grained, red mica-granite-gneiss, associated with bands of coarse mica-schist.
At Cape Haven station near the northern entrance to the bay, pink and gray mica-gneiss prevails, and is cut by many large dikes of red pegmatite composed largely of perthite, with some quartz and mica. Schists forming one of the islands of the harbour contain many well-developed crystals of pyrite, up to an inch cube.
The northern and eastern sides of Bylot island appear to be wholly formed of crystalline rocks, without any of the capping limestones found upon the other islands of Lancaster sound.