GEA CIAETS LUDLIES IN \Giez 2 NIGAIND, 199 
that here the ice finds its greatest expanse. The glacial phe- 
nomena we are to consider relate, therefore, to the widest part 
of the widest mer de glace of the northern hemisphere. 
Inglefield Gulf indents this broad tract to a depth of about 
100 miles, or one-seventh of its width. The trend of the gulf 
is a little north of east. It has a breadth of from eight to twelve 
miles. There are two notable branches on the north side, 
McCormick Bay and Bowdoin Bay, both of which have become 
memorable from their association with Lieutenant Peary’s work, 
the former having been his headquarters during his first explora- 
tion, and the latter, during his second. On the south side there 
are likewise two arms, Olriks Bay and Academy Bay. 
General geology.—Ywo great series of rocks are represented 
in the district, the one an ancient complex crystalline terrane, 
probably Archean, the other, a clastic series of unknown age. 
The crystalline series is chiefly composed of gneisses in which a 
strong hornblendic tendency is manifest, some parts, indeed, 
being largely hornblende. There are also embraced in it some 
belts of quartzite which bear a general resemblance to the quart- 
zites of the Algonkian series of the upper Mississippi and Lake 
Superior regions. 
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 the 
existing topographic expression before the sandstone series was 
laid down upon it. If the sandstone were removed, the relief of 
the topography would apparently not be less than it is now, and 
not very different from it in general aspect. 
Lying conformably upon the red sandstone is a somewhat 
thicker series of pinkish gray sandstone. This has a quartzose 
constitution much the same as that below, but somewhat exceed- 
ing it in hardness. While well indurated, it is unmetamorphosed. 
