48 ME. J. E. MARE ON THE TARNS OE LAKELAND. [Feb. 1 89 5, 



Discussion. 



Dr. H. E. Mill said that he had been much impressed by 

 the Author's admirably clear explanation of the singular fact that 

 the outlet of Smallwater flowed not along the bottom, but along the 

 side of the valley. He congratulated the Author on having taken up 

 the systematic study of the tarns, a class of depressions belonging to 

 a type entirely distinct from the larger hollows of the valley-lakes. 

 Some connecting-links, such as Hayes "Water and Easedale Tarn, 

 would probably be found on examination to bridge the gap. He 

 thanked Mr. Marr for his paper, the conclusions of which he, as a 

 geographer, was glad to accept without criticism. 



Prof. Botd Dawkins remarked that the Author's conclusions as to 

 tarns being simply valleys blocked up by morainic debris applied 

 merely to the cases cited in the area under consideration, and did 

 not touch the general question as to the possibility of some basins 

 being the result of ice-erosion. In his opinion the greatest lakes of 

 the American continent were clearly proved to have been ancient 

 valleys blocked up by glacial debris. 



The Eev. H. H. Winwood did not venture to enter into the 

 question of the origin of tarns ; but, having had the opportunity of 

 visiting Easedale Tarn in company with the Author, and on other 

 occasions, he had examined the outlet of the stream and found that 

 the water had cut its way through an old moraine, which was 

 especially observable on one side. 



Prof. Bonnet expressed the interest with which he had listened 

 to Mr. Marr's valuable paper. Though he personally thought little 

 of the erosive action of glaciers, he believed that he had seen one or 

 two true rock-basins in corries or cirques. One of the most striking 

 examples which he had seen was the Lago di Tremorgio, south of the 

 Ticino Valley, where live rock could be observed at the only opening, 

 for it had been displayed in an artificial cutting. 



Mr. Btjtley and Dr. Blaneoed also spoke. 



The Aethoe, in reply, stated that his observations referred only 

 to the tarns of the Lake District, and he considered that further 

 evidence was required to show that tarns existed in rock-basins. 

 He was looking forward to the publication of Dr. Mill's maps of the 

 lakes of Cumbria, and hoped after their publication to study (with 

 the co-operation of Prof. Nicholson) the nature of the hollows in 

 which the larger lakes of Lakeland lie. 



