[Joseph] Le Conte
main range, and vast ice floes from the Tuolumne above Hetchy Hetchy broke over into the Merced basin by the "Yo Semite, Cascade and Tamarac tributaries. Most of this Tuol- umne ice had to cross the great canon reaching from near the Soda Spring to Hetchy thus.
Yo Dr Joseph Le Conte.
Yo Semite, Dec 17. '72
Dear Le Conte.
My seasons work is done. I have had one gen- eral view of the Merced basin above Yo Semite and am aston- ished at the magnitude of the ancient glaciers with which it was universally flooded, and of the work which they accom- plished. The entire basin is one glacial monument covered with inscriptions, some graved in small line characters too minute for our eyes, others dif- ficult to read because of their magnitude, the depth of canon and height of dome composing the separate letters thereof. 00634
I do not hope to make any adequate translation of what I have seen and heard. I only hope to make you come and see for yourself. If you could be made to feel the truth that is here you would come like an atom to the magnet without a thought of time or duties. (I wonder that manu- factured proprieties and duties should so shackle and cobweb God's human flies.) But next year you will have what you call vacation, when mankind and your wife will let you come, but I set a few baits to make sure of you.
The Merced ice basin was bounded by the summits, and by two spurs which once
reached to the summits, viz. the Hoffman and Obelisk ranges, thus -
In this basin not one island existed. All its highest peaks were washed and overflowed by the ice. Starr King. South Dome - and all. Some ice from about Mt Lyell and Dana, ect broke over the Hoffman range into the Tuolumne basin below the Soda Springs, thus cutting off the Hoffman from the
because many of these mountains continued to shelter and feed fragmentary glacierets long after the main trunks to which they belonged were dead, like those of the present day crouching behind Mt Lyell, Red Mountain, black Mt, &c., steepening all their north sides. The streams of this re- gion were never much lar- ger than they are at present. - None of the upper Merced streams give any record of floods greater than the spring floods of to-day.
Cross section of glacial and water basin of Nevada a few miles above little Yo- Semite [drawing]
Glacialer st[illegible] clear and unwashed as low as the point indicated by arrows, also at the same point there [in margin: are unmoved glacial boulders.]
The Tuolumne canon above Hetcy-Hetchy is deep as Yo Sem- ite, and the fact that so much ice flowed easily [underlined: over] it into the Merced basin gives some idea of the Magnitude of the Gla- ciers of this region. It is only the vastness of the Gla- cial pathways of these Moun tains that prevents our see- ing them at once. The English Alphabet would puzzle a professor if written large enough, and if each letter were made up of many small- ler ones. The bed of one unbro- ken ice river is [frequentl?] veiled with forests], and a net work of tiny water channels. The great central Glaciers of Yo-Semite did
not come squeezingly, gropingly down to the main valley by the narrow, angular, tortuous [deleted: channels] canons of Tenaya & Illilowette, but all of this Sum- mit ice was united above the Valley, even toward the later glacial period, and flowed grand- ly and directly over all the upper domes like a steady wind, while its lower, bottom currents went mazing and swedging down among the crooked and dome blocked channels below. Glaciers have made every mountain form of this whole basin, and even the Summit mountains are only fragments, reminants of their pre-glacial selves. Every Summit wherein are laid the Sources - the wombs
of glaciers is steeper upon the north than the south side, because of the difference in [underlined: depth] and [underlined: duration] be- tween exposed and sheltered glaciers, and this difference in steepness between the N and S. Side of Summits is greater on the lower Summits, as those of the Obelisk group. This tells us something of the Glacial climate. Such Mts as Clouds Rest, Starr King, Cathedral Peak, &c. do not come under the general law, because their contours were determined by the ice that flowed above them, but even among these basin mts we frequently find marked difference of steepness upon their N. and South Sides,
1872 Dec 17
Original letter dimensions: 20.5 x 25.5 cm.
Muir, John, "Letter from [John Muir] to [Joseph] Le Conte, 1872 Dec 17." (1872). John Muir Correspondence (PDFs). 1497.
Reel 02, Image 0997
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