154 PROCEEDINGS OF THE 



Along the shores of Lough Swilly a light blue clay is found about 

 forty feet above the present sea level. It contains numerous 

 fragments of shells, mostly recent species, and seems to mark the 

 old sea-beach. In one bed, a mile from Ramelton, where the clay 

 is used for brickmaking, I got a part of a deer's horn, which is 

 very completely fossilized, and from the evidence the specimen 

 itself presents, I have no doubt it was used at one time as a small 

 pick These post-glacial and recent clays require working up in 

 the north of Ireland. 



Bog is the surface deposit over a large portion of the county. In 

 some places I have found it as much as twenty feet deep, and trees 

 occur abundantly, the fir being more frequent than the oak. I 

 was surprised on visiting, some time ago, Inniskeragh (an island 

 in the Eosses district, west of Torry), to find the sea beating 

 against a seven-feet cliff of bog. I could trace patches of it, too, 

 below the water, and each wave had a peaty fringe — the debris 

 torn from shore and sea bottom. In different places round 

 these Eosses islands the stumps of trees can be seen sub- 

 merged, and further west, the structures known as "smelting 

 pots," and which were used some centuries ago for reducing 

 iron, have been seen from a boat on a calm day in three fathoms 

 of water. 



There can be no doubt that these facts point to a comparatively 

 recent depression of the land, and from all I have observed, the 

 depression is still going on, although at no place have I found the 

 phenomena so marked as in the Eosses district. 



Botany. — The influence of plant life in modifying geological 

 conditions is not so often referred to nor so well understood as 

 its influence in modifying climate. An instance of the former 

 came under my notice last summer, in Fannctt, thirteen miles 

 north of Eamelton. The shores of that district are very sandy, 

 and no part of them more so than Glassagh, so that the kelp 

 made from the seaweed cast in there brought only a low price. 

 However, some years ago the Earl of Leitrim planted all the 

 bare sand above high water mark with "bent," and ever since 

 then the sand of the shore has been gradually disappearing, till 

 now it consists of clean stretches of granite rock and beautiful 

 pebbly strands, enabling the cottars to secure the weed free from 

 sand, and get the highest price for their produce. The rationale 

 of the change is this : — The small river which flows into , the 



