OCR Text |
Show 282 TIERRA DEL FUEGO. June, 1834· the solid rock. In Georgia, situated in the very same latitude, Cook, speaking of the great ice-cliffs at the head of every harbour, says, "pieces were continually breaking off, and floating out to sea, and a great fall happened while we were in the bay, which made a noise like cannon." He adds, " It can hardly be doubted, that a great deal of ice is formed here in winter, which in the spring is broken off, and dispersed over the sea. Mr. Sorrell, the boatswain of the Beagle, who has long been accustomed to these seas, informs me, that at this season he has seen small icebergs, with mud and gravel on them, floating from the shores. I have heard from another quarter of the same circumstance. Captain Hunter* says, he met numerous ice-islands in this neighbourhood, · and that "many were half black apparently with earth from the land, to which they had adhered, or else with mud from the bottom on which they had been formed." By the latter method large fragments might easily be transported, and unless the iceberg should be upset, they would never be discovered. Nevertheless, the islands of ice floating in the southern ocean, and especially those occurring far south, appear generally to be quite free from all impurities excepting the dung of seafowl. Captain Biscoe, who extended his enterprising researches so far towards the antarctic pole, informs me in a letter that he never observed in a single instancet any mud or fragments of stone on the numerous icebergs which he encountered during his voyage. Glaciers occur at the head of the sounds along the whole western coast of the southern part of South America. Looking at the chart I find sixteen places mentioned : besides these I know of several others, such as those in the Beagle channel and at the foot of Mount Sarmiento. The sounds, moreover, were not all traced to the head, and it is in this part that the glaciers most frequently occur. Of the sixteen referred to, many include several frozen arms coming down • Hunter's Voyage to Port Jackson, p. 102. t Mr. Sorrell says, that he once saw an iceberg to the eastward of South Shetland, with a considerable block ?frock lying on it. June, 1834. GL ACIERS. 283 from one vast body of ice. In the Canal of the Mountains, for instance, no less than nine descend from a mountain, the whole side of which, according to the chart, is covered by a glacier of the extraordinary length of twenty-one miles, and with an average breadth of a mile and a half. It must not be supposed that the glacier merely ascends som~ valley for the twenty-one miles, but it extends apparently at the same height for that length, parallel to the sound ; and here and there sends down an arm to the sea-coast.* There are other glaciers having a similar structure and position, with a length of terr and fifteen miles. I will now specify a few of the more remarkable cases, taken from Captain King's paper, to which I have so often referred. The canal of St. Andrew is said by Lieutenant Skyring to be " suddenly and boldly closed by t~em~ndo~s and astonishing glaciers." The highest mountam m tlus part (Mount Stokes) was ascertained during our ascent of the river of St. Cruz to be 6200 feet, and this certainly exceeds considerably the height of the general range. A~out ninety miles to the northward, Sir G. E~e's Sourtd, in. the latitude of Paris has its several arms termmated by glaciers. Mr. Bynoe, the 'surgeon of the Beagle, who accompanie~ the boat when this part was surveyed, informs me that about mid-channel, and more than twentg miles from the head of the sound, there were great numbers of floating masses of ice. Standing in the boat he supposes he saw about fifty : he, together with four of the boat's crew, landed on one, which although only two or three feet ~bove the surface ~f the water, felt quite steady, and eas1ly supported therr weight. On the surface, in the central part, a mass of granite, of an angular form, was partly embedded ; and the • I may remark that in the chart, the greater number of ~he ~ree.ks which receive the glaciers, have crosses drawn in front, whiCh sJgmfy proJ· ectm· g masses of roc k . •A .ft er wh a t we have seen in the Beagle channel, I suspect that they are detached masses brought down by the overwhelming force of the glaciers. |