Prof. Tyndall on the Conformation of the Alps. 171 



years ago I had an opportunity of inspecting the Val Tournanche 

 from Breuil to Chatillon. This year I crossed the Cimes 

 Blanches from Breuil, wandered over the ancient neves of the 

 place, penetrated the higher ramifications of the Val d'Ayas, 

 and everywhere found the sculpture of the ancient ice. Crossing 

 the Col Betta Furka, and looking down the Yal du Lys, the work 

 of the glacier which once proceeded from the slopes of the 

 Lyskamm was immediately manifest. I traced the action 

 through this noble valley, as far as Gressonay St. Jean ; every- 

 where on the valleys' flanks the same truth was proclaimed. 

 What air and water have accomplished since the disappearance 

 of the glaciers are mere scratches of the tooth of time, in compa- 

 rison with the mighty furrows which had been previously 

 ploughed out. 



From Gressonay I crossed the Col de Val d'Obbia to Alagna, 

 and everywhere I trod upon ground deserted by the ice. Like its 

 neighbour of the Lys, the Val Sesia also formed the bed of a 

 mighty glacier. From Alagna I crossed the Turloz ; the traces of 

 the ice are here magnificent, and on the flank of the Val Anzasca, 

 opposite the place where the glacier from Mont Turloz joined 

 that from Macugnaga, the rocks are wonderfully worn ; all up 

 the Macugnaga valley to the base of Monte Rosa the same graDd 

 evidences appear, forcing upon the mind the existence of a state 

 of things so extraordinary that, were the proofs less strong, the 

 imagination would shrink from any attempt to realize it. I have 

 repeatedly explored both the Saasthal and Nicolaithal ; both 

 of them are glacier channels ; an expanse of particularly finely 

 rounded rocks may be seen on the side of the Saasthal at the 

 place where the road turns up to the valley of the Fee. 



Having finished the exploration of this part of the country, I 

 felt a strong desire to visit the Jura, and to observe for myself 

 the boulders scattered over its slopes. I accordingly went to 

 Neuchatel, visited the celebrated Pierre-a-Bot, and examined 

 the general character of the moraine-like matter which is strewn 

 over the slopes. Granite boulders were abundant, being in many 

 cases quarried for building use. The Jura, as is well known, 

 yields no granite ; it is composed of limestone. Whence, then, did 

 these blocks come ? Limestone is a partially soluble rock, and 

 hence, when long exposed to the air, although it may preserve 

 the general form imparted to it by the grinding-action of a 

 glacier, it does not retain the finer striae which enable one to 

 determine the direction of motion. I therefore sought for slabs 

 of limestone from which the protecting soil had been recently 

 removed, and was fortunate enough to find some very fine ones, 

 in which the glacier-scratches were marked with perfect distinct- 

 ness. I determined the direction of these scratches at three 



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