34 
Geology. 
the investigations of earlier observers. With the exception of the 
clastic and igneous deposits of the Disco province, the forma- 
tions south of Cape York belong to an ancient crystalline series 
of the granitic or, more strictly, the gneissic type. These have 
usually been referred to the Archean age, and everything which I 
saw was confirmatory of the correctness of this reference, al- 
though, from the absence of any Paleozoic beds in contact with 
the senes, the opinion rests chiefly upon the lithological character 
of the rocks themselves, their remote connections with the Paleo- 
zoic series of north Greenland and their general geographic re- 
lations to the terranes of the mainland. 
In the region of Inglefield Gulf, the ancient crystalline rocks 
are bordered by sandstones and shales of unknown age. While 
the full extent of this clastic series could not be determined, even 
within the region visited, because it reached back under the ice 
cap, there were abundant grounds for the belief that it is but a 
narrow skirting belt. It was seen to be interrupted at frequent 
points by the coming of the crystalline series out to the shore. At 
other points, bays and valleys were observed to reach back across 
the clastic belt to the crystalline series behind. At other points where 
the clastic series occupies the whole coast and forms the front of 
the plateau, the glacial tongues brought crystalline rocks from 
beyond, and this is true in the case of Redcliffe Peninsula, whose 
ice cap is entirely separate from the inland ice and whose diame- 
ter is but about 15 miles. It is obvious from this and similar 
cases, that the crystalline rocks rise to the summit of the plateau 
within a few miles of the coast. 
The clastic series embraces three distinguishable members. 
The lowest is a red sandstone which attains a thickness of per- 
haps 1000 to 1500 feet. Its beds possess moderate massiveness, 
lie at low inclinations, and rest unconformably upon the crystal- 
line series. The discordance is very great and indicates that the 
crystalline terrane had assumed essentially its present attitude, 
had undergone very great erosion, and had approached its pres- 
ent topographic expression before the sandstone series was laid 
down upon it. If the sandstone were removed, the relief of the 
