634 OREGON AND NORTHERN CALIFORNIA. 
mination of talcose spots of a lighter shade than the colour of the 
slates. Some of the slates contain actinolite in slender crystals, and 
large nests of this mineral are not uncommon near the first locality 
mentioned, presenting radiated and fan-like crystallizations. 
In these talcose slates, near Yerba Buena, I observed, in two in- 
stances, an imbedded fragment which appeared, at the time, to be a 
fossil, half obliterated in its characters. The specimens were after- 
wards misplaced, and I cannot decide, in my own mind, whether these 
were actual organic remains or not. 
A protogine or talcose granite is another of the varieties connected 
with the talcose series. It was met with in the Shasty Mountains, 
having milk-white and grayish colours. One variety consisted of 
quartz and albite, with sufficient talc to give the rock a greasy lustre. 
Another variety, resembling much a granite, was composed of white 
quartz and yellowish feldspar in rather coarse grains, with spots of 
chlorite or olive-green talc. ‘The rock is not durable, owing, in part, 
to some iron in its composition which rusts on exposure and colours 
the rock red. ‘This protogine may be seen passing into the common 
talcose and prasoid rock, with which it occurs, and not into the 
granites. It occasionally contains yellowish or greenish-white pieces 
of a compact material, appearing like an imbedded fragment of indu- 
rated clay. 
Much of the hornblende schist in the Shasty Mountains contains 
talc, and specimens of both hornblende and talcose rocks may be col- 
lected, in some instances, from the same square rod. Some portions 
of the diallage rock are also talcose. 
Serpentine is largely developed in high ridges to the northwest of 
the Shasty Mountains, (west of the last encampment before entering 
the mountains,) where it has the softness and translucent edges that 
usually characterize this mineral. The general colour is a dark green ; 
but it is sometimes mottled with a light grass green, and green dial- 
lage is abundantly disseminated through certain portions of the rock. 
There are also seams of amianthus or asbestus. This rock is also 
found in the Shasty Mountains, but where examined by the writer 
it was a harder variety; it may be traced in its passage into the 
ordinary talcose rock. Its colours are often variegated like verd 
antique marble. 
From the above descriptions it is obvious that all the rocks enume- 
rated, from the serpentines to the granite, belong to one and the same 
series. In the Shasty Mountains, the pure albitic and feldspathic 
