90 Bulletin of Laboratories of Denison University [Voi. xi. 
pathetic expression the indelible impress of the contrition of 
the Magdaline. Indian superstition found it impossible to pur- 
sue even the implacable duty of vengence under the placid 
eyes of the lady Magdalena and the spot became a place of 
refuge. 
A special interest therefore attaches to this mountain, 
whose eastern slope rises abruptly from the valley, though the 
integrity of the escarpment is injured by a considerable frozen 
cascade of trachytic lava that curls over the brow of the moun- 
tain. It may be that some part of the mountain was the thea- 
tre of volcanic activity during the trachitic period but no ade- 
quate evidence is at hand to support that view. The base of 
the mountain is composed of brown and gray andesite to the 
hight of about 350 feet above the valley. Presumably this is a 
part of the great flow dating from the time of the eruption of 
Little Baldy and the extrusion of the great sheet of andesite 
and other basic eruptives in the region. The same rock crops 
elsewhere in the valley and we may ascribe the greater hight to 
which it rises here to the protection offered by the capping of 
later lavas which the ages of erosion have not sufficed wholly 
to remove. The andesite is not freely visible, being generally 
covered by the talus, thus it happens that its possible metallic 
resources have not been exploited, though the inevitable pros- 
pector has recognized the rock as similar to ore-bearing rocks 
elsewhere and burrowed into the veiny portions at various 
places about the mountain. The first deposit above the ande- 
site was evidently of an explosive nature and was probable at 
or near the beginning of the acid period. It consists of banded 
trachyte tuff containing fragments of the subjacent andesite 
and also irregular pieces of dark obsidian like that which fol- 
lows. Some of the pebbles are rounded and it may be sug- 
gested that the beds have been deposited during a period of in- 
termittent aqueous flows and explosive eruption. The average 
thickness of this flow may be about 200 feet. Next above 
this, and forming evidence of a more placid type of eruptive 
activity is a bed of impure black obsidian. The lower layer of 
the obsidian .contains fragments from the tuff, while the upper 
