214 CRUISE of THE neptune 
geological appendix, is shown on the present map. On the coast 
of the mainland, west of the isthmus, the limestone formation 
is found resting on the granites of Lake wittersted. Northwest 
from the isthmus the southwest coast of Boothia presents a 
range of granitoid hills, running northward, but becomes 
fringed by a low border of limestone near Cape Isabella, and 
. this increases in width to the north, till an extensive flat lime- 
stone region is found in the vicinity of the magnetic pole.' 
at Bellot strait a junction occurs between the granite and 
horizontal beds of Silurian limestone. 
' The entire western portion of Prince of wales island is 
composed of Silurian limestone, which in the extreme west, at 
Cape Acworth, becomes chalky in character and non-fossilifer- 
ous, resembling the peculiar Silurian limestone found on the 
west side of Boothia Felix.' 
The northern and eastern shores of North Somerset are of 
limestone, usually rising from the water in precipitous cliffs. 
These were examined at Port Leopold, where the cliffs rise sheer 
1,000 feet from the sea. The bedding of the limestone is very 
distinct, and the face of the cliff has been sculptured by every 
runlet, so that between the horizontal and vertical markings the 
cliffs resemble on a gigantic scale the fluted walls of a castle. 
Fossils were collected from the lower beds of the cliff by 
m'clintock, but none were collected on the present voyage. 
Islands of Group IV. 
The discovery of the Silurian limestone of the southern cliffs 
of North Devon and Cornwallis was made by Parry, while his 
collection 'of fossils was supplemented by those found by the 
Franklin search expeditions. Our knowledge of the geology of 
Ellesmere was, previous to the Sverdrup expedition, mainly due 
to the work of Feilden and De rance in connection with the 
British expedition of 1875-76. Mr. P. Schei, the geologist   
