366 A. Geikie—Archean Rocks of the Wahsatch Mts. 
I submit, therefore, that the facts taken by themselves and 
without reference to any preconceived opinion or theory, are 
these: Ist. A large mass of granite* on the Wahsatch Moun- 
tains ascends with an oblique or transgressive boundary line 
from certain schists and quartzites across the Paleozoic series 
up into the Upper Carboniferous horizons. 2d. The rocks as 
they approach the granite manifest increasing metamorphism ; 
the limestones pass into white granular marble, and other rocks 
have assumed the character of schist. 8d. Among the Car- 
boniferous limestones and other rocks around the main mass of 
granite, there occur, in different places, dikes or veins of granite- 
porphyry, like those usually met with in a similar position. 
he conclusion which I would draw from these facts is that 
the granite is intrusive, and is later in date than the Upper 
Carboniferous rocks which have been metamorphosed in con- 
tact with it. Mr. King speaks of there being possibly two 
granites, one metamorphic and one intrusive, but both of 
rchzean date. I could observe no reason for making any 
subdivision in the granite mass. e somewhat foliated 
arrangement in certain portions of the granite is not uncommon 
toward the periphery and even within the central portions of 
intrusive bosses, 
The section across the Wahsatch range, placed below rie 
No. III (east half) of the Geological Exploration of the 40t 
Parallel, seems to me to bear the strongest evidence against 
Mr. King’s own reading of the structure of the mountains. If 
t h 
twelve miles high! that being the horizontal length of the plat- 
form of granite into which the rocks dip. In the next place It 
structure 
of the ground. That the latter is the natural interpretation of 
* There can be little doubt that though partially interrupted at the surface by 
overlying formations it is really all one granite mass. 
