474 Proceedings of the Royal Irish Academy. 



depth is 88 feet, and half a mile east of the island, just opposite the 

 entrance of Buno-^ven Bay, the sounding was 103-7 feet. 



Two sections were run along the shores of Bunowen Bay, proving 

 the water even close to the shore to he very deep, in some places one 

 hundi'ed yards only from the shore being from 35 to 47 feet. 



Sections were run from this bay to the south of Church Island, 

 proving some considerable depths. A remarkable one is about sixty 

 yards south of the spit of land forming the southern point of the 

 island, where there is a sudden drop of 84 feet in hard rock. 

 In fact, all along the southern side there is very deep water, while 

 that on the northern is very shallow. 



Other sections were run from Church Island to Leggamore Bay 

 (Holywell), and from this to Wolf Island, near the Garavogue river. 

 The greatest depths in these were 34 and 41 feet respectively. 



Another section was obtained from Toberconnel Bay, southwards, 

 towards Eockwood, in the narrowest part of the lake. The depths 

 here are considerable — half a mile from the shore they reach 99 feet, 

 and a Kttle further south 96 feet. 



Besides the above, several isolated soundings were taken, but these 

 possess at present no particular interest. 



The season being then too advanced, the work was stopped. It 

 will be continued this summer, and it is hoped that a full Eeport, 

 with chart and sections, will be ready for presentation to the Academy 

 during the next "Winter Session. 



Summary of Facts. — It would be premature as yet to enter into 

 the geological aspects of the subject, but the following points may be 

 noted : — 



1°. The great and frequently-recurring irregularity of the bottom 

 of the lake. 



2°. The preponderance of depth (with few exceptions) on the 

 south side, along which a great line of fault runs. 



3°. That many of the deeps of the lake nearly coincide with the 

 direction of known lines of faults in the shore rocks. 



4°. That while the direction of the ice-flow, as indicated by the 

 markings, in the district immediately around the lake is towards the 

 IS'.W. or jST.jS'.W. (that is, across it), the principal line of the lake is 

 in an east and west direction. 



5°. That the numerous small islands in the lake form sub- 

 aqueous cliffs, which cannot be regarded as due to ice action, seeing 

 that the "crag," or cliff, faces indifferently north, south, and east. 



On the whole, therefore, the evidence at present seems to point to 

 the origin of the lake as due to faults ancl subsidences in the first 

 place, followed by chemical erosion of the limestone rocks along the 

 lines of fault. That ice-action assisted in the details of the carving 

 out to some extent there can be little doubt ; but these matters will 

 be fully entered into in a subsequent Eeport. 



