24 MAN AND THE GLACIAL PERIOD. 



comes down from an unknown distance in the western in- 

 terior, bearing two marked medial moraines upon its sur- 

 face. On nearing tide-level, the valley through which 

 it flows is about three-quarters of a mile in width ; but, 

 after emerging from the confinement of the valley, the 

 ice spreads out over a fan-shaped area until the width of 

 its front is nearly three miles. The supply of ice not be- 

 ing sufficient to push the front of the glacier into deep 

 water, equilibrium between the forces of heat and cold is 

 established near the water's edge. Here, as from year to 

 year the ice melts and deposits its burdens of earthy debris, 

 it has piled up a terminal moraine which rises from two 

 hundred to three hundred feet in height, and is now cov- 

 ered with evergreen trees of considerable size. From 

 Chilkat, at the head of Lynn Canal, to the sources of the 

 Yukon River, the distance is only thirty-five miles, but 

 the intervening mountain-chain is several thousand feet in 

 height and bears numerous glaciers upon its seaward 

 side. 



About forty miles west of Lynn Canal, and separated 

 from it by a range of mountains of moderate height, is 

 Glacier Bay, at the head of one of whose inlets is the 

 Muir Glacier, which forms the chief attraction for the 

 great number of tourists that now visit the coast of south- 

 eastern Alaska during the summer season. This glacier 

 meets tide-water in latitude 58° 50', and longitude 136° 40' 

 west of Greenwich. It received its name from Mr. John 

 Muir, who, in company with Eev. Mr. Young, made a 

 tour of the bay and discovered the glacier in 1879. It 

 was soon found that the bay could be safely navigated by 

 vessels of large size, and from that time on tourists in 

 increasing number have been attracted to the region. 

 Commodious steamers now regularly run close up to the 

 ice-front, and lie-to for several hours, so that the passen- 

 gers may witness the "calving" of icebergs, and may 

 climb upon the sides of the icy stream and look into its 



