1 894.] 



THE BRITISH NATURALIST. 



217 



up against the sandstone wall, and there was the same sandstone to 

 furnish debris and blocks from a continuation of the same drift, but 

 there is an agent of removal which I must go a little into the physical 

 geography of the district to make plain. Looking southwards into the 

 glen of which Tore and the Eagle's Nest are the portals, you see an 

 assemblage of mountain forms which extend to the watershed. They 

 are all over 2,000 feet high. Passing westwards, the ridge that com- 

 mences with the Eagle's Nest offers peaks that are called Tomies and 

 the Purple Mountain, and then separated by the narrow pass of the 

 Gap of Dunloe there rises up a cluster of the loftiest mountains in 

 Ireland — Magillicuddy's Reeks. These are among the first hills that 

 the Atlantic clouds, heavily charged with moisture, meet with, and the 

 precipitation of water is sometimes enormous. A large portion of the 

 drainage from the Reeks finds its way down a long slope called the 

 Black Valley, forming in its course two or three little lakes, and then, 

 when reinforced by the contributions from the hills which extend 

 southwards, a much larger one — the Upper Lake, about one-and-a- 

 half miles long, but not so wide." 



The exit from the Upper Lake is by a small side opening, which 

 is of comparatively recent formation, and which is so inefficient as an 

 exit that I have seen the water of the lake raised many feet by one 

 day's rain. Before this side opening was made the drainage must have 

 flowed along the axis of the valley, and the water have stood at a con- 

 siderably higher level. It must then have passed through a short 

 valley called the Long Range, and have entered the Lower Lakes, 

 then one, and also at a much higher level. 



This is the agent of removal, then, by which all trace of the presence 

 of the glacial sea has been removed from this portion of the district. 

 It is not necessary to assert that the precipitation was greater in past 

 times than to-day ; but in any case the rate of escape must in glacial 

 times have been much slower. If it fell in the shape of snow a glacier 

 would be formed, and that it did so result the marks of glaciation in the 

 Black Valley, along the Upper Lake and the Long Range, and on 

 the sides of Tore, are most convincing evidence. 



In tracing the course of this glacier of the Reeks we are confronted 

 by the same problem that Switzerland and other countries of ancient 

 ice offer, viz., the high level, keeping in mind the amount of the present 

 drainage. Yet the ice markings cannot be gainsaid, and we have no 

 other resource than to believe that part of the ice stream left the 

 general mass and flowed over the col which separates the Black Valley 

 from the Gap of Dunloe, and receiving increments from the side 

 valleys finally emerged on the north side of the Gap, where its terminal 



* Note. — This is generally considered the most beautiful of the lakes, having several 

 ell-wooded islands, and being entirely shut up by hills on all sides. 



