Botany of the Shores of Lough Ntagh. 39 



Colgan, knowing Mr. Davies' interest in the matter, had 

 given him references to its continental range of distribution. 

 There it was known to occur in the regions adjacent to the 

 Jura Mountains. Yet, it remained that in this island it was 

 restricted to the seaside. Lough Neagh, so far as he could 

 ascertain, being the only exception. In the course of last 

 summer he had seen there another plant, a sand spurrey, 

 Spergiilaria rupestris^ which held the same position. How 

 came these plants ? Not carried by sea-birds which visit 

 the lake, since in that case the}' might be expected at the 

 margins of other large lakes, also frequented by sea-birds. 

 There were considerations which pointed to geological 

 possibilities. One incident bearing on this he might mention. 

 In 1874 the British Association met in Belfast under the 

 presidency of Professor Tyndall. That meeting was most 

 memorable, and of some of the discussions that then arose, and 

 were for some time continued, there were those of them who 

 retained a lively recollection. On that occasion a well-known 

 geologist, Mr. Hardman, brought forward a paper on " The 

 age and mode of formation of Lough Neagh." He sought 

 to prove that the clays overlying the basalt were lacustrine 

 deposits of Pleiocene age. Two years later, during a visit to 

 Crumlin in company with Professor Hull, they found in the 

 clay at that place fossil shells, the only fossils save those 

 of plants previously known to occur in the Lough Neagh clays. 

 They were considered to be fresh water shells, and their 

 discovery was held to be in support of a theory that there 

 was a former very large Lough Neagh, also fresh water, with 

 an area probably twice as great as at present. This aroused 

 so much interest that three of iheir members, his friends, Mr. 

 W. Swanston, Mr. Stewart, and Mr. Wright, made a thorough 

 investigation of the deposits, which led to widely different 

 conclusions. The shells, which were in loose drift over-lying 

 the boulder clay, were found to be, not fresh water shells, but 

 those of the common mussel. It was found also that the deposit 

 contained several species of microzoa now living along their sea 



