#hsrt

[aandrezel]

[aandrezel]

When topography is as beautiful as at Donner Pass, it is not an easy matter to see through it, but if you’re looking for structure you might start with the granite. In all the country from Nevada to the pass, the volcanic cap makes its appearances, but always as veneer–eroding everywhere, opening windows, and ultimately suggesting the bewildering mass of the underlying granite. This is the Sierra batholith. Geologists reserve that term for the largest bodies of magmatic rock. A batholith, as defined in the science, has a surface of at least forty square miles and no known bottom. For the latter reason, it is also called an abyssolith.

John McPhee, “Annals of the Former World”

[aandrezel]

[aandrezel]

[aandrezel]

[aandrezel]

[aandrezel]