ARCTIC ISLANDS 117 
The country, formed of the limestones and other Palaeozoic 
rocks, differs in its physical character from that already des- 
cribed. On the northern islands, where these rocks attain a 
considerable thickness, the land rises in abrupt cliffs directly 
from the sea. The summits of these cliffs vary in elevation 
from 1,000 to 3,000 feet, while the country behind is a table- 
land rising in steps inland, the front of each step being a cliff 
usually of much less thickness than the initial one by which the 
land rises from the sea. In the more northern islands the higher 
portions of these tablelands support ice-caps generally much 
thinner than those covering the adjoining Archaean tablelands. 
The coasts composed of these flat-bedded limestones are deeply 
indented by narrow bays or fiords in the valleys of the more im- 
portant streams; each small stream and rill flowing off the land 
has left its sculptured mark upon the cliffs, so that the whole 
resembles, on a great scale, the banks of a stream cut into a 
deep deposit of clay. This minute sculpturing of the rocks 
points to their having been elevated above the sea for a very 
long period, during which time the streams were actively at 
work cutting their valleys down to the sea-level. 
These high abrupt cliffs are characteristic of the islands 
on both sides of Lancaster sound and to the northward 
of it. 
The limestone islands of Hudson bay and that portion of 
southwest Baffin underlain by these rocks are very low and 
flat, with shallow water extending several miles from their 
shores. 
Those northern islands, wholly or in part formed of the 
Mesozoic rocks, are characterized by low shores and no great 
elevation inland. At Ponds inlet, where an area of Tertiary 
deposits occurs, the country overlying it forms a wide plain 
deeply cut into by the streams that drain it. 
