GEOLOGY. 
169 
No. 17. Green-stone porphyry, imbedded in and forming one side of the lower part of 
the cliff on which the north-eastern flagstaff' is erected. 
No. 18. Green-stone porphyry, with fewer imbedded crystals of felspar, traversed by 
veins of milk-quartz. — C. 
Kotzebue’s sound. 
The bounding shores of Kotzebue’s Sound for the most part rise by perpendicular 
cliffs, either directly from the water or from a shelving beach. In some places the land 
is remarkably low, and only so much raised as to render the idea probable, that it is an 
alluvial formation, the result of the accumulated mud and sand brought down by large 
rivers and thrown up by the sea. The cliffs are in part abrupt and rocky ; others are 
made up of falling masses of mud, sand, and ice. The first or rocky cliffs, predominate 
to the southward of a line drawn from the north-west side of Eschscholtz Bay to the 
south-eastern part of the Bay of Good Hope. The second, or diluvial cliffs complete 
the remaining north-east side of the sound, and take in part of the south-side of Eschs- 
choltz Bay. Low grounds chiefly border the Bay of Good Hope, and form the land of 
and around Cape Espenberg. The history of these mud cliffs, and of the remarkable 
organic remains contained in them, has been given in vol. 1. Appendix. 
Three geognostic formations are exposed on the shores of Kotzebue’s sound. 
The primary, (consisting of clay-slate, mica slate with beds of primitive lime-stone, 
talc slate, alum slate, &c.) forms the whole of the rocky coast. The diluvial and allu- 
vial formations constitute the remaining part of the adjoining country. 
In giving a more particular account of the primitive formations, I shall commence 
where it first shows itself, in Choris Peninsula, between the Bay of Eschscholtz and 
Kotzebue’s Sound (see pi. 1. Geology). This division is in the form of a narrow penin- 
sula, variously indented, and lying longitudinally in a north and south direction. The 
northern part of it is separated from the southern by a narrow low neck, and assumes 
the shape of a round and somewhat conical eminence, surmounted by a flat hut-like 
peak, the sides of which rise a few feet nearly perpendicular above the surrounding- 
surface. The whole height may be about 600 feet from the level of the sea. Both 
sides of this peninsula terminate in rocky cliffs, which towards the west are 150 or 200 
feet high, stratified, unbroken, and dipping to the west at an angle of 30°. On the east 
side, towards Eschscholtz Bay, they are less high and more broken, presenting no evi- 
dent dip, and are composed of a greyish mica slate, with very few included minerals. 
The cliffs expose a general rock of mica slate in loose and falling fragments. The dip 
is to the north-east in the first promontory looking to Eschscholtz Bay, at an angle of 
60°. The mica slate is here of a greenish hue, the mica considerably predominating, 
with garnets, veins of felspar inclosing crystals of schorl, and fissures filled with quartz. 
Nearly midway between this promontory and the low neck, a bed of milk quartz pro- 
trudes at the top of the cliff, and marks its locality at a distance by the large white 
blocks which have fallen down and remain unaltered by the seasons. Still nearer the 
neck, a narrow bed of lime-stone above the mica schist, above ten yards high and five 
