Santa Barbara Channel^ etc — Yates. 43 
or the water of the stream may have cheeked the progress of 
the lava by congealing it. The character of the lava sheet, 
scoriaceous and vesicular above and below, massive and com- 
pact in the middle, corresponds to what is observed in modern 
lava flows. The surface of lava in contact with the air or 
water, gives off its imprisoned steam through multitudes of 
little steam holes. This reduces the surface of the sheet to a 
rough, spongy, vesicular mass, whilst the liquid lava flows on 
below. The same occurs with the under surface in contact 
with the cool or damp ground. Portions also of the scoriaceous 
top surface fall off the end of the advancing sheet and are 
rolled underneath it. As the molten stream advances, the 
spongy or scoriaceous surface is broken up into clinkers which 
are rolled along on the top of the liquid stream, and become 
piled up in confused masses where there is any check or ob- 
stacle to the flow, such as the clift' and river in the present in- 
stance. 
How comparatively old, or recent, may be the date of this 
eruption, it is not easy to determine. There are tall fir-trees 
growing in the throat of the crater. I did not see any sign of 
hot springs or gas emanations in the vicinity, such as are 
common in recently extinguished volcanoes, nor are volcanic 
rocks particularly abundant in the immediate neighborhood. 
This occurence seems to be an isolated one. 
This interesting locality is accessible by the morning train 
of the Rio Grande railroad between Leadville and Glenwood. 
The lava flow is close by the track, but the crater is between 
three and four miles back to the north, in the hills. The blue 
grey color of the lapilli capping the hills can be distinctly 
seen from the train, and marks the locality of the volcano. A 
resort called Siloam Hot Springs has recently been establish- 
ed not far from this spot and would make a good stopping 
place for some geologist to more leisurely and thoroughly ex- 
amine this interesting locality. 
NOTES ON THE GEOLOGY AND SCENERY OF THE ISLANDS 
FORMING THE SOUTHERLY LINE OF THE 
SANTA BARBARA CHANNEL. 
By Dr. Lorknzo Qoisdix Yatics, Santa Barbara, Cal. 
The entire group or series of islands, forming the southern 
line of the Santa Barbara channel off the coast of southern 
