GEOLOGY. 
167 
lower part, and a kind of projecting gallery of curved pillars near the top. It is sur- 
rounded on all sides by a luxuriant vegetation. This basalt contains nodules of olivine, 
but wants the basaltic hornblende so universally diffused over the island. In no other 
place indeed did I find it absent. Olivine and zeolite, although common, are in smaller 
quantities, and steatite rather rare. 
Specimens from this island are varieties of tufa, lava, and basalt; — olivine, meso- 
type, analcime, basaltic hornblende, steatite. — C. 
AVATSCHA BAY, KAMTSCHATKA. 
An extended view of the country around the Bay of Avatscha ranges over swelling 
plains, thinly covered with wood, and in the summer with a deep green vegetation, till 
it comes to the lower mountains disposed in long barren ridges, among which some lofty 
and isolated mountains rise abruptly to 8,000 or 12,000 feet. On the 1st day of July, 
1826, the lower range had their sides thinly furrowed with white snow, whilst the more 
lofty had their tops entirely veiled in it. From one of the highest of these (Avatshin- 
skaia), to the north-east of the bay, we could distinctly perceive volumes of white smoke 
issuing at more than one opening, and the surface of the snow on its sides blackened, as 
if by a recent fall of volcanic ashes. 
The isthmus that forms the western side of the small harbour of Petropaulski is 
composed of clay-slate, containing various coloured jaspers, and dipping at an angle 
varying from 30® to 45° to the south. Between the village and Rakowena harbour the 
clay-slate ceases and is succeeded by serpentine containing amianthus. 
On the left hand of the entrance of the harbour of Rakowena, all around its shores, 
the cliffs are high and perpendicular, and composed of trap, quartz and serpentine. 
Columnar basalt shews itself in several places. The second perpendicular pro- 
montory on the right side of the entrance to the harbour of Rakowena is composed of a 
porous basalt, in perpendicular pentagonal and hexagonal columns of moderate size, 
reposing upon horizontal strata of slate-clay, apparently hardened by the action of heat. 
Columnar basalt is seen in the face of the cliff under the north-east signal station, re - 
posing upon an extensive bed of porphyritic green-stone. This rises up from under 
the basalt towards the south-west, but the cliffs outside this again assume somewhat of 
the columnar appearance for a short distance, when the tufa seems to preponderate, and 
is continued to the outer boundary of the bay on the north-eastern side. 
On the western side of the bay basalt is disposed in horizontal columns, forming, 
as it were, a thick wall, standing out from the cliff, and having its base washed by the 
sea. In the face of the tufaceous cliff behind, there are curved columns of the same 
nature. 
The western part of the bay, towards the entrance, and the coast facing the open 
sea, appear to be chiefly tufaceous, and frequently of a brick colour. At Paratunka 
there are thermal springs which are probably in a volcanic formation. 
The clay-slate that forms the high isthmus on the north-west of the harbour of 
Petropaulski is continued into the higher hill, between it and the lake on the road to 
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