[Jeanne C.] Carr
means I was enabled to measure the flow of the glacier with great exactness. Examining this stake in 24 hours after setting it, I found that it had been carried down about 3/16 of an inch At the end of four days I again examined it & found that the whole downward motion was 13/16 of an inch showing that the flow of this glacieret was perfectly regular. In accounting for these narrow lane canons so common here I had always re[illegible]ed] them to ice action in connection with special conditions of cleavage, & I was gratified to find that their formation was still going on. This Hoffman glacieret is about 1000 feet long by 15 to 30 feet wide. & perhaps about 100 feet deep in deepest paces. Now there Mrs Carr I must[in margin: hasten back to the Mtns, I'll go tomorrow] 00625[There is a line through whole page] 4  The Sierras adjacent to the Yosemite Valley are composed of Slabs of granite set on edge at right angle, to the direction of the range or about N 30° E, S 30 W Also lines of cleavage cross these running nearly parallel with the main range. Also the granite of this region has a horizontal cleavage or strabfication. The first men- tioned of these lines have the fullest development & give direction & character to many valleys & canyons & determine the principal features of many rock forms No matter how hard & domed & homog[illegible]eous the granite may be it still possesses these lines of cleavage wh require only simple conditions of moisture, time etc for their development. But I am not
1872 Oct 8
Original letter dimensions: 20.5 x 25.5 cm.
Reel 02, Image 0953
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