for trachyte. Many of the masses It appears are only 
apparently dark from the weather stain and coatings of iron. 
In the slides, however, ';ere numerous fragments of darker 
rock, a dark gray slaty looking porphyry of ter apparently 
brecciated, Midway In the steep mountain face there are 
heavy outcrops of a dull pinkish or reddish porphyry that 
is quite firm and compact but has frequent layers of whitish 
material that give the rock a woody or grained appearance 
and are probably flattened vesicles filled with caleereous 
or other matter. See specimen. 
These rocks so far as I could determine are not bedded 
with any detree of regularity but to my right, midway 
between Red Mountain and Mount Sheridan and near the 
summit of the connecting ridge there is a long precipice 
face in which a regularly vedded series of rocks occur, 
I was quite unable to spare time to visit this outcrop. 
It is not impossible that the weathering in the other 
spines or amphitheatres of this face of the group was 
favorable, .1 more distinctly bedded character might be 
detected. The summit of the mountain -has a small area of 
brecciated porphyry £.15 ? ) which has a thickness of, 
probably 40 feet. The included masses are angular and 
various sizes and materials (all volcanic). Some of the 
fragments are as much as 4 and 5 inches and perhaps even more 
