1883.] NATURAL SCIENCES OF PHILADELPHIA. 251 



torrent from the Muir glacier, it was evident that during a glacier's 

 existence the underflowing river might often become dammed, and 

 the torrent diverted, carrying glacial deposits to sections of country 

 long distances away from the track of the glacier, and through 

 portions of country over which glaciers had never flowed. And 

 there might be immense glacial deposits left by a glacier constantly 

 retreating, and after many subsequent years, by the diversion of 

 the glacial river, a new channel and new remains may be deposited 

 througli the mass, even by another distant and distinct glacier. 

 This was actually the case in this instance. This stream had 

 torn its way through immense hills of glacial deposits, many 

 hundreds of feet deep, exposing to view the trunks, still standing 

 erect, of a buried forest, though not a stick of forest-growth, 

 except a few alders and willows, could be seen anywhere in the 

 vicinity, as far as the eye could reach, and suggesting that the 

 original deposit was not made by the existing glacier, the waters 

 of which now tore their way through the huge hills. 



Tlie question would now arise as to the souice of the water 

 supplying the subglacial liver-bed. It would be well to carry 

 some ascertained facts along with us in this examination. An 

 iceberg of more than usual dimensions had got aground in 

 Glacier Bay, and, having one good, fair face, it was found by 

 careful soundings that the vessel could be placed close alongside. 

 At seven and a half fatlioms, we were able to hitch on to the gi-eat 

 block, the sides of which projected far above our deck. The 

 surface of this berg exhibited, in a small way, all the features of 

 a tract of land : lakes, rapids, waterfalls, hills and valleys ; in 

 some places, earth and stones. To-day the course of a water- 

 channel might be in one direction, till a falling piece of ice or earth 

 would block it up, when a source would be opened for a new direc- 

 tion, and the little streams, once started, would form in a short 

 space of time Wide and d- ep chasms. A piece of rock, by its 

 dark color attracting the sun's raj's, would sink deep into the 

 berg, while earth, porous and non-conducting, would prevent 

 melting; and thus we would have mounds on the berg where the 

 surroundings, clear of earth, would be melted away. The action 

 of the ^un on melting portions of the berg was interesting. The 

 thermometer was but 42° ; yet on any side where the suu fell, 

 even at this low temperature, the little streams and rivulets were 

 coursing their way to the great ocean around. But on tlie 

 northern slopes, there were barely any streams, except such as 

 originated on t!ie sunnier sides. In fact, it was demonstrated 

 that wherever the sun struck on ice, even at a low temperature, 

 the deposition of water occurred. What he had carefully noted 

 on this iceberg he had before noted on high mountain peaks: 

 there would be always some melting from the face of a snow- 

 bank, no matter how low the temperature, where the sun shone- 

 fairly on it, and the water would sink to the bottom of this mass. 

 On this iceberg there were clefts and rifts and wells furrowed by 



