THE ICE AGE. 99 



mountains, ruggedly advances, carrying limestone bowlders, and termi- 

 nating three miles from the head of the pass in a steep precipice one 

 hundred feet high, where its final burdens are discharged down the 

 mountain. Snow-beds or small glaciers are of constant occurrence at 

 the heads of the ravines, and the cool water-brooks which traverse the 

 slopes spring from their melting edges. In Butna Valley the traveler 

 passes for two miles among huge bowlders, then crosses a moraine, 

 and finally reaches a plain encircled by lofty mountains, some of which 

 reveal resplendent pyramids of snow which " bind " into a glacier, filling 

 the head of the valley. Its Surface is obscured by masses of rock and 

 gravel, and beyond its present limits similar proofs of its ravages lie in 

 bewildering confusion. From the valley of Nubbra the traveler beholds 

 the encircling peaks brilliant and luminous in the blaze of countless 

 snow-fields, while icy currents, confluent in larger glaciers, stream from 

 the distant heights. One of these, approached through avenues of bowl- 

 ders, is half a mile wide, and black with a coverlid of stones and dirt. 

 Neio-hborinof ravines conceal kindred masses whose extremities retire 

 from terminal heaps of bowlders, landmarks of their former expansion. 

 The magnificent glaciers north of Sassar are conspicuous and famous. 

 The large glacier passes down the mountain-side, ploughing a deep fur- 

 row through an alluvial plain and plunging into the Shayuk River, whose 

 waters eddy and boil from underneath it. Two moraines accompany it, 

 one of enormous blocks and sixty feet high, outside of its present 

 shrunken area, formed in the glacier's former strength, and a smaller 

 one upon it. In furrows, fifteen and twenty feet deep, upon its surface 

 are sunk strings of rocks imbedded in the icy matrix, and released in oc- 

 casional showers from its terminal cliflFs upon a talus of fragments thus 

 accumulated. In the Shigri Valley and at Zanskar, enormous glaciers 

 are gathered together in companies. Some are literally buried beneath 

 the extraordinary heaps of rocks and detached slabs which are caught 

 upon them from shattered cliff and stony avalanche. They work their 

 way underground, while grass and flowers decorate the desolate cover- 

 ing which conceals them. The valleys of Thibet show unmistakably 

 the past presence of extensive glaciers. Moraines and traveled blocks 

 reach low down into them, often three thousand feet lower than the 

 existing termini of the glaciers. 



If, leaving the inhospitable terraces of Thibet and the sublime and 

 unrivaled summits of the Himalayas, we traverse the ice-covered table- 

 land of Greenland, we shall encounter the same phenomena as those 

 we have examined in the Alps, in Norway, and in India, but so magni- 

 fied in extent as to become continental, and in a measure reconstruct 

 the picture of a world hidden beneath a universal mer de glace. Green- 

 land stretches down from those vast and unexplored regions, whose lim- 

 its encircle the pole, in a broad wedge-like peninsula, deeply fissured 

 by fiords and bays, its margins abruptly rising in mural precipices, and 

 bearing upon its bosom the oppression of an illimitable glacier. From 



