GEOLOGY 221 
These show that the lower limestone is of Silurian age, about 
the horizon of the Niagara. 
Similar conditions prevail in the cliffs at Beechey island, 
where a large collection of fossils was obtained from the lower 
limestone beds, while others, picked up loose, but evidently 
fallen from the cliffs above showed that the upper beds passed 
close to if not into the Devonian, as stated in Appendix IV. 
Similar Silurian limestones constitute the island of Corn- 
wallis, to the westward of North Devon, while in the remaining 
Parry islands farther west the Silurian strata are lost beneath 
the Devonian and Carboniferous rocks of those islands. 
DEVONIAN. 
The work of the older geologists, which was summarized by 
Haughton and later by Dawson, took no account of the Devon- 
ian in their divisions of the Palaeozoic rocks of the islands north 
of Lancaster sound. All the lower limestones were classed as 
Silurian, while the overlying sandstones were placed in the 
Carboniferous. Fossils of Devonian age were collected, by the 
expedition of 1876, from the northern part of Ellesmere, but 
their occurrence and relations were only finally settled by Schei 
as given above. From his observations it is plain that the upper 
part of the limestones and the lower 1,000 feet of the overlying 
sandstones are of Devonian age. The early explorers were not 
trained geologists, and it could hardly be expected that they 
would discover the thin bands containing fossils in these great 
thicknesses of barren beds. Owing to this supposed lack of fos- 
sils the rocks were separated into Silurian and Carboniferous 
almost wholly on lithological differences, the limestones being 
classed as Silurian and the sandstones as Carboniferous. 
There is no doubt that Devonian rocks are included in the 
Carboniferous of the western Parry islands, but as they occur 
only in the cliffs underlying the Carboniferous beds that cover 
