Jan. 28, I 



NA TURE 



299 



cation until those members of the Royal Society who 

 have studied the geology of Egypt can have opportunity 

 to discuss it fully. J. WlI.LIAM Dawson 



December 28, 1885 



NOTES ON THE " MUIR GLAC/ER" OF 

 ALASKA 



IN a recent number of Nature (vol. .\x.\ii. p. 162) 

 an abstract is made of a San Francisco newspaper 

 account of the " Great Glacier" of Alaska. This account 

 is not very accurate, and as I spent a few hours on this 

 glacier during a flying visit to Alaska in the summer of 

 1884, I think my observations may be worth recording. 

 I have heard that some desciiptions by American ob- 

 servers have already been published, but have not been 

 able to procure them. However, as tliere are one or two 

 features to which it may be useful to draw the attention 

 of future explorers in this region, I will give my observa- 

 tions just as I made them, and apologise beforehand if 

 they should be found to overlap those of others. 



On August I, 1884, I took passage from Victoria, Van- 

 couver Island, on the steamer — on this occasion the 

 Ancoi! —which carries the monthly mail from ports on 

 Puget Sound to Sitka, Alaska, and eight days later we 

 steamed up the long fiord known as " Glacier Bay," 

 which opens into the Chilcoot Inlet, being then not far 

 from latitude 59" N. and longitude 136^ W. of Greenwich. 



On either side of us high snow-capped mountains 

 bordered the fiord, and in their recesses we could see 

 glaciers of all sizes. One large mass filled a deep valley 

 on our left, and reached nearly down to the sea, being 

 apparently only separated from it by a ridge of moraine ; 

 and everywhere little patches of blue rested in all the 

 coulees near the mountain-tops, and showed by their trail 

 of bare striated rocks and long strings of moraine how 

 much further they must recently have extended. 



Here and there a small island rose above the waters of 

 the fiord, and, by its bare rounded outline and moiiton- 

 nieii surface, gave evidence that it, too, had once been 

 overspread by the ice. The Indians say that one of these 

 islands which is now above a mile distant from the Great 

 Glacier, was embedded in the ice during their recollection, 

 and I was told that early Russian charts of the coast do 

 not show this fiord at all, but make note of a line of ice 

 cliffs near its present entrance ; but though the fiord 

 has undoubtedly been at one time filled with ice, I cannot 

 think that the period was so recent as this would indicate. 



All round us the waters of the bay were strewn with 

 masses of floating ice of beautiful colour and fantastic 

 outline, but none were large. Right ahead, a gleam- 

 ing wall of ice rose up out of the water and com- 

 pletely blocked the fiord, extending with a slight outward 

 bulge from shore to shore. This was the " Great Glacier," 

 or the " Muir Glacier," of Alaska. 



In the account in Nature it is stated that the height of 

 the ice-wall is 500 feet, but I think this is an exaggeration. 

 The master of our steamer thought its highest point 

 might reach 450 feet ; my own estimate would place it 

 much lower even than this. Where I stood beneath it on 

 the eastern shore I do not think it was more than 240 feet 

 high, judging from the better-known height of an abutting 

 cliff of sand and gravel presently to be described ; but as 

 the upper surface of the glacier appeared to be slightly 

 domed, so as to be highest in the centre of the bay and 

 lowest near the mountains, 1 should say that near the 

 middle of the fiord the cliffs might be nearly 100 feet 

 higher than where I stood ; but in my opinion they nowhere 

 exceeded 350 feet. 



The breadth of this ice-wall was about three miles. Huge 

 masses were constantly splitting from it and sliding down 

 into the sea with a loud dull roar. As they slid they 

 raised a white dust-like cloud, and when they fell into the 

 water great waves leaped in upon them and dashed high 



up the ice clift", rebounding and causing every now and 

 again a broad deep ground-swell which we could watch 

 as it rapidly swept towards us. 



The water through which we passed had changed when 

 we first entered the fiord from the deep dark blue of 

 the outer channel to a beautiful pale green, and now be- 

 came quite clouded and of a milky greenish-white ; and 

 when we came nearer the glacier strong springs were 

 observable, bursting up through the sea-water so as to 

 rise slightly above its level. These were some little 

 distance from the ice-cliff, whicli must have projected 

 forward under water. 



After having failed in an attempt to make fast to a 

 grounded mass of ice — the largest near us — which rose 

 up in pinnacles to the height of our somewhat stunted 

 topmasts, we anchored near the right, or eastern, shore. 

 Our party was then put ashore on a fine beach of washed 

 sand and shingle, about half a mile from the foot of the 

 glacier. 



This beach is formed by the action of the waves on a 

 mass of morainic material which is piled up irregularly 

 between the shore and the bare mountain-side, and, 

 where we landed, sloped back almost insensibly into 

 the glacial gravels. But nearer the glacier the moraine 

 had been cut back so as to form a low cliff, which in- 

 creased in height as it approached the ice. 



This cliff exhibited a clear and very interesting section, 

 of which I made a sketch on the spot, shown in Fig. i. 



It, 



K\ 



'•'"I." 



s. I.— Sketch Section of Cliff .it the head of Cbcier Bay, Alaska, on tlie 

 eastern shore, adjoining the glacier, Aug. 9, 1884. Length of section 

 about 400 yards ; height at X about too feet._ 



A, Eastern end of terminal precipice of Muir Glacier, a nearly vertical 

 wall of very clear blue ice, without stones : the ice shows lines of 

 bedding tow.lrds the base, which are strongly curved over a donie- 

 rhaped cave (s) from which issues a strong current of muddy water ; 

 this cave is filled by the sea at high tide ; full height of ice wall, which 

 is about 240 feet here, is not shown. 



B, Flange of very stony, dirty ice, apparently descenrling and flowing 

 forward from the main mass of the glacierat a point some distance behind 

 the line of section : about 60 feet thick at X X: this passes 1 



forfc 



els 

 thickn 



the 



, but rapidly 



c. Rubble of angular and water-worn boulders and pebbles mixed 

 with sand and clay; derived from the melting of the stony ice, B, whose 

 lower layers are scarcely distinguishable from this bed. 



D, Steep cliff of evenly-bedded sand and gr.avcl ; pebbles small and 

 water-worn ; shows signs of erosion at junction with c, but the bedding 

 is not disturbed : height at A'.. ..A" 40 feet. 



E, A small boss of stony, bluish-gray clay resembling till, outcropping 

 below the sands and gravels : full of small water-worn pebbles. 



F, Similar l)Oss of fine gray clay without stones : no observable 

 bedding. 



NoTiis.— In the above figure that part of the section m.irked^ A is not on the 

 same plane as the rest, which recedes about 2o yards — the width of the sea- 

 beach. 



A narrow gully (.y) h.ad been excavated between A and d by water 

 derived Irom the melting ice. and the lower part of the section was here 

 obscureil by talus : c crossed the head of this gully and jomed the main 

 mass of the glacier, but it was difficult to study this junction, as the ice of 

 c overhung the gully, and was constantly shedding masses into it. 



The size of the patches of clay marked E and F is somewhat exaggerated in 

 the section to m.-ike them apparent. I saw only a small surface of each rising 

 above the beach in the cliff-foot ; but from the manner of their outcrop I 

 think they may form part of a clayey base on which the gravels rest. 



I was not able to give much time to the study of this 

 remarkable section, but was able to satisfy myself on the 

 following points : — That a considerable thickness of 

 evenly-bedded, water-worn gravel and sand was in close 

 proximity to an almost vertical wall of ice, if not actually 

 abutting on it. That this bedded gravel and sand was 

 covered for some distance by a mass of dirty ice, full ot 

 stones, which was connected in some way with the main 

 mass of the glacier. That the bedding of this deposit 



