94 [Proc. B. N. F. C, 



it ultimately reaches the lake has been the source of much con- 

 jecture, but the general opinion is that the water finds its way 

 again above ground in the form of the springs of Sullatober, 

 nearly two miles lower down. To test this the Belfast Vv^ater 

 Commissioners have made various experiments. A ton of salt, 

 a quantity of copperas, and several bags of what a neighbouring 

 farmer denominated " shillun seeds," were put in at Lignaca, 

 but of the salt and chemicals no trace was found in the water 

 at Sullatober, and of the chaff only a few doubtful grains came 

 out again at the springs. When the Lignaca stream was tem- 

 porarily diverted some years ago, however, the Sullatober spring 

 almost entirely ceased. Possibly, as in the case of other lime- 

 stone rocks, the stream may pass through underground basins 

 capable of holding a large quantity of water, in which whatever 

 was put in above would be lost, so that, although the flow of 

 water might remain even, it would be almost impossible to 

 trace anything from its entrance at -the swallow hole above to 

 its exit by the spring below. On the other hand, when Lough 

 Mourne was frozen over during the recent severe winter, there 

 were always dangerous spots on the ice, which marked the 

 presence of hidden springs, so that it is still an open question 

 whether some of the water does not go into the lake. The 

 swallow-holes occur in the line of a fault, the basalt of one side 

 of the hollow being replaced by the white chalk on the opposite 

 side. The hollow itself has been probably excavated chiefly out 

 of the chalk, the solid matter having been removed by the 

 carbonic acid of the water in a state of solution. 



Before leaving Lignaca a meeting was held — the President, 

 R. Young, Esq., C.E., in the chair — and several new members 

 were elected. 



The party then proceeded along the shore of the lake, which 

 has recently been acquired by the Water Commissioners. The 

 land round has also been purchased, and a very moderate embank- 

 ment will enable a large quantity of the winter rains to be stored 

 here. The lower end of the lake is formed by a bank of boulder 

 clay: through this several shafts have been sunk over forty feet to 



