Nov. 20, 1879] 



NATURE 



69 



from bottom to top. It reminded him of the wonderful 

 ice-polished precipice on the left bank of the Aar glacier, 

 above the Grimsel. It was clear, therefore, that not only 

 was this second canon old ; it was older than the glacial 

 period ; it had supplied a channel for the glacier that 

 ground its way out from the mountains. Endeavouring to 

 estimate the minimum thickness of the ice, he traced with 

 the eye the glaciated surfaces up to the summit of the 

 declivity — a height of at least Soo, perhaps 1,000 feet, — and 

 they evidently went still higher. In going further up the 

 valley, he found that the blocks of granite and gneiss, 

 dropped by the glacier as it melted, went far above 1000 

 feet. He got them on the shoulders of one of the great 

 hills overlooking the valley 1,600 or 1700 feet above the 

 plain. The ice, therefore, must have been not less than 

 1,600 or 1,700 feet thick, and must have passed across in- 

 tervening ridges into adjacent valleys. It thus appeared 

 that not only did glaciers occupy the valleys of this region, 

 but that some of them were of such thickness as to deserve 

 the name of ice-sheets, covering the whole surrounding 

 region. 



Leaving the Yellowstone Valley, the party struckthrough 

 the forest, and after a two days' ride reached the Upper 

 Fire-Hole Basin of the now famous geyser region. Prof. 

 Geikie gave a general sketch of the aspect of this district, 

 and described the operations of one or two of the geysers 

 which he witnessed. After the long ride through an arid 

 region and dusty wastes, he tried hard here to get a pool 

 to wash in, but could find nothing below 212°, and the 

 only chance of getting a warm bath was to find some hole 

 where the water had had time to cool after flowing out of 

 the hot crater. The whole ground was honey-combed 

 with holes, each filled with gurgling boiling water. One 

 geyser, affectionately and gratefully known as "Old 

 Faithful," went off with wonderful regularity every 63 

 minutes ; the others were more capricious. The singular 

 depositions round the orifices of eruption and round 

 the margins of the pools on the cones were referred 

 to, and among other interesting phenomena an account 

 was given of the " Devil's Paint Pot," a mud geyser, 

 throwing out white and brilliantly-coloured mud, boil- 

 ing like a great vat of rather thick pasty porridge, and 

 surrounded with small mud cones, each of which had 

 formerly been a point of emission. 



In quitting the Yellowstone region, it was impossible 

 not to reflect with admiration upon the labours of the 

 explorers who had first made known the wonders of this 

 remote and inaccessible region. The Reports of Hayden 

 and his associates were found to be most trustworthy and 

 useful. Nor could one forget the sagacity with which 

 Hayden proposed, and the enlightened liberality with 

 which Congress enacted, that for all time the Yellowstone 

 Region should be a tract set apart as a national park for 

 the instruction and recreation of the people. 



On the way out of the mountains by Henry's Lake and 

 the head of the Snake River branch of the Columbia 

 River, the travellers came upon a party of armed Indians, 

 who explained that they were out of their reservation on 

 their way to a council of Indians in Montana. As the 

 great outbreak of the White River Utes, who killed Major 

 Thornburgh and his men, took place only about ten clays 

 or so later, and as there was then some excitement among 

 the tribes to the West, the geologists, though pleased at 

 the time to have seen the noble red man in his war-paint 

 among his native wilds, came to think that on the whole 

 they might congratulate themselves on having seen no 

 more of him. Only last year the Yellowstone country was 

 dangerous from roving bands of Indians, several lives 

 having been lost in it. Leaving the Indians, who pursued 

 their northward course in a bee-line, the travellers held 

 westward along the edge of the vast basalt plateau of the 

 Snake River — one of the most extensive lava fields in the 

 world. A great plain, thousands of square miles in 

 extent, had there been deluged with dark basalt. No 



cones or eminences appeared from which the lava migh 

 have been poured. Perhaps the eruptions took place from 

 open fissures. Here and there later cones had risen upon 

 the plain, belonging, doubtless, to some of the later stages 

 of the volcanic activity. Some of these cones still retained 

 w : ell-shaped craters. 



Reaching eventually the basin of the Great Salt Lake, 

 one of the first geological features that struck the tra- 

 vellers was the evidence of the former vast expansion of 

 the Salt Lake. Lines of terrace ran as prominent features 

 along the sides of the mountains, the highest of them 

 standing at a height of nearly 1000 feet above the present 

 level of the lake. Striking into some of the canons 

 descending from the Wahsatch Mountains into the Salt 

 Lake Basin, Prof. Geikie found the rocks smoothed, 

 polished, and striated by the glaciers that had come down 

 from the heights and had brought with them great quan- 

 tities of moraine matter. Mounds of rubbish blocked up 

 the valleys here and there, and some of them he observed 

 to descend to the level of the highest terrace. Hence 

 when the Salt Lake extended far beyond its present area, 

 and was about 1000 feet deeper than now, the glaciers 

 from the Wahsatch Mountains reached its edge and shed 

 their bergs over its waters. Bones of the musk-ox had 

 been found in one of the terraces, showing that an arctic 

 fauna lived in this region during these cold ages. 



On his return journey the Professor resumed the exami- 

 nation of the surface deposits of these prairies. Coming 

 out of the Colorado Mountains, he noted, in connection 

 with the gravel formerly observed, great quantities of a 

 peculiar grey clay or loess inter-stratiricd with the gravel, 

 and here and there containing a small terrestrial shell 

 (Succinia vermeta). It w-as a freshwater deposit, one 

 that had been swept by the waters coming down from the 

 mountains over the prairie. It might be regarded as 

 marking one of the phases in the period during which the 

 gravel and sand were being thrown down. Tracing the 

 gravel mounds over an extensive tract, he found that they 

 had been deposited irregularly, as might have been the 

 case from the action of water escaping tumultuously and 

 interruptedly from the melting ends of the ice. The 

 water currents would traverse the plain now in one direc- 

 tion, now in another. The whole prairie, for many leagues 

 east from the mountains, must have been flooded with 

 water derived from the melting ends of the great glaciers. 



By these successive floods the gravel and sand were 

 spread out irregularly over the plain, and during the same 

 prolonged period of ablation of the ice there were here 

 and there greater streams or periods of more muddy 

 water, when the fine grey loess was diffused over the flats, 

 as has taken place in the valleys of the Danube and 

 Rhine. No doubt some of the fine detritus may be 

 travelling eastward still, for though the rainfall over 

 much of the prairie country is exceedingly slight, it may 

 suffice to give the fine parades of sand and gravel an 

 intermittent movement to lower levels. 



NOTES 

 We tal<e the following from the Times: — The medals awarded 

 and recommended by the Council of the Royal Society for the 

 present year are : The Copley medal to Prof. Rudolph J. E. 

 Clausius, of Bonn, for his well-known researches upon heat ; the 

 Davy medal to Mr. P. E. Lecoq de Boisbaudran for his discovery 

 of gallium ; a Royal medal to Mr. William Henry Perkin, 

 F.R.S., for his synthetical and other researches in organic 

 chemistry ; and a Royal medal to Prof. Andrew Crombie 

 Ramsay, F.R.S., for his long-continued and successful labours 

 fu geology and physical geography. These medals will be pre- 

 sented at the anniversary meeting of the Society, on December I, 

 when Mr. W. Spottiswoode will deliver bis first annual addres 

 as president. 



