The rocks found on the north side of the Archer plateau, in the eastern part of Ellesmere to the north of Cape Sabine, are very interesting geologically, as they show the only trace of an unbroken sequence of beds from the Huronian up through the Cambrian to the Silurian limestones so widely distributed on the Arctic islands. These rocks are described by Schei as follows:
‘At Cape Camperdown, on Bache peninsula, is found granite overlain by an arkose-like conglomerate sandstone, in flat strata, the dip being north-northwest. Its thickness here probably does not exceed 500 feet, though the contour swells to considerably greater magnitude by reason of intrusions of diabase, occasioning an additional thickness of perhaps 300 feet. At its upper part this sandstone merges gradually, by interstratification, into a series of gray, sandy and marl-like schists and limestone conglomerates. From a few inches up to a couple of yards in thickness these conglomerates and schists, continuously interstratified, build up a series 600 to 900 feet in thickness, interrupted by two compact beds of yellowish-gray dolomitic limestone about 150 feet in thickness. These are again overlain by a series similar to the underlying one, excepting that here the limestone conglomerates exceed the schists.’
‘In a detached block, in all probability originating from one of the two 150-foot beds, were traces of fossils, of which one, Leptoplastus sp., can be identified. In another detached block, whose mother rock is not known, was found Anomocare sp. It may be said with certainty after the finding of these fossils that this series contains deposits of the Cambrian age.’
‘The second series of conglomerates is overlain by a light grayish-white limestone in a bed some 300 feet in thickness, observed in the midst of the section of Cape Victoria Head. Indistinct Orthoceras, Lichas and Symphysurus assign this limestone to the Lower Silurian period.’
‘Above the othoceras-bearing, light-coloured limestone bed are some less extensive strata of alternating limestone and quartz-sandstone, and finally a 100-foot bed of close brown limestone of which certain layers are fossiliferous, and gave an Asaphus, traces of other Trilobites and some Gasteropods.’
‘Following the direction of the dip to the north side of Princess Marie bay we find it again, though seemingly somewhat abrupter, in the limestone beds of Norman Lockyer island. A fauna with Halysites sp., Zaphrentis sp., Orthisina sp., Rhynchonella sp., Leperditia sp., Illœnus sp., &c., assigns this limestone to Lower Silurian. It is again found with its fauna at the base of Cape Harrison; in this case with a thick super-incumbent bed of marly sandstone, quartz-sandstone, and finally extensive limestone conglomerate. This also occurs near the shore in Cape Prescott, indicating by its presence in the strike of the limestone of Norman Lockyer island the disturbance undergone by these tracts.
‘The line along which this disturbance took place is refound on the west side of Franklin Pierce bay, where the beds of limestone conglomerate dipping from the heights of Cape Harrison are cut off in the strike by a limestone, dark-gray in colour and broken into a breccia.’
In another place Schei hints that the rocks of the Cape Rawson beds, consisting largely of dark shales and impure limestones, found along the northern parts of the eastern shores of Ellesmere, may be of Triassic age, in sharply folded troughs of the older rocks, and consequently much younger than Cambrian, to which age they were referred by Fielden and De Rance.
Writing of the Silurian beds found on the southern coast of Ellesmere, Schei describes them as answering to the northern series, and their occurrence is as follows:—
‘There are at Havnefjord, in Jones sound, above some layers of quartz-sandstone, which entirely cover the gneiss-granite there, a series of limestone conglomerates with marly schists and pure limestones of a thickness of 1,200 to 1,500 feet. These are again overlain by a series of beds at least 2,000 feet thick, of hard, impure limestones, brown or yellowish-gray in colour, and often remarkably heavy.’