262 Proceedings of the Royal Irish Academy. 



are parallel with the former, we have eleven fissures (not in all cases open 

 throughout their whole length) all absolutely parallel with one another, and 

 ranging from 20 to 250 feet in length, while the height in the majority of 

 cases is not less than 20 feet, and probably considerably more. The greatest 

 width of any one of those is 5 feet, while at the ends they thin down to a few 

 inches. In only comparatively few cases could the actual ends of the fissures 

 be reached owing to their extreme narrowness. Their floors are horizontal, 

 despite the fact that the stratum dips at about 35° south. The fissures have 

 probably been widened to their present form by the solvent action of water 

 trickling down their walls. The openings which lead from one fissure to 

 the next are in all cases comparatively low, and seem to be formed by the 

 breaking down of the dividing-wall. At the northern extremity of some of 

 the Maze fissures the walls come together at the floor ; but there is a lower 

 extension of the fissure some 10 feet below the general level, which can be 

 entered through one or two holes. A low tunnel, running at right angles to 

 these fissures, connects their lower extension, and this tunnel, at the time of 

 our visit, contained a few inches of still water. 



In certain other cases the fissures seem to have been widened by the action 

 of running water ; for example, the passage from the entrance to the House 

 of Commons ; the Cathedral, and Sadlier's Cave. The passages in the Old Cave 

 leading from the entrance to the G-reat Chamber are also fissures enlarged 

 in the same way. It may be taken as a general rule that all the passages 

 which have a north and south direction are of one or other of these two types, 

 and are usually of considerable height, the lowest being about 4 feet at the 

 southern end of the Sand Cave, whilst in the majority of cases the roof can 

 only be faintly seen, and must be at least 30 feet above the floor. 



It is a fact worthy of note that, with three exceptions, all the water met 

 with in the New Cave lies in the line of one fissure, i.e., at the northern end 

 of the Maze, at the western end of the Maze tunnel, near Cust's Cave, to the 

 south of the Scotsman's Cave, and in the fissure to the south of the Four 

 Courts. This fact seems to indicate that these points lie along one of the 

 chief lines of weakness in the cave. Of the other places in this Cave where 

 water is found, two lie in the line of a parallel fissure, one being in the Sand 

 Cave, and the other the Eiver in Eoute II. 



The Garrett Cave and O'Leary's Cave, which both lie at a higher level than 

 the other chambers and passages of the New Cave, seem to have been formed 

 as the result of great slips, possibly of the roofs of some chambers which 

 formerly underlay the present floors. In both cases the floor is shattered 

 into immense blocks of rock ; and whereas in most other places it is difficult 

 to find a loose stone, all being cemented together with stalagmite, here every 



