1883-1884.] 275 



There seems practically to have been no dissent from this 

 explanation of their origin. 



I think myself, however, that the use of the term lake is a 

 little misleading, and that the deposits were not formed in any 

 larger sheets of water than would be called tarns among our 

 mountains. Their deposition is too irregular, and the water 

 must have been too impregnated by iron for them to have been 

 truly lacustrine, and I have noticed that little sediment is formed 

 in actual lakes in basaltic areas. The association together of 

 heavy closed pine-cones and fruits, with objects so easily floated 

 away as well preserved dead leaves and pine-needles, would 

 appear to show that the water must have been almost stagnant, 

 for in true river deposits such associations would not be likely 

 to occur. The irregular and almost twisted nature of the bed- 

 ding, and the presence of breccias or conglomerates, and the 

 generally coarse nature of the matrix, is on the other hand, 

 entirely opposed to their having been formed in stagnant water, 

 and the transverse section especially, at Ballypalady, has every 

 appearance of having been due to rapid and shifting water, of 

 very varying volume. 



Detailed sections published in the works of Portlock, Tate 

 and Holden, Bailey, and Kinahan, differ slightly. The quarries 

 have greatly changed in form, and the variability of the beds 

 renders it difficult to reconcile the older sections with what is 

 actually existing. The plant bed on the west side of the rail- 

 way appears to be from 10 to 15 feet thick, the greater part of 

 this mass being conglomerate, or at least a gritty ore, and the 

 fossils confined to thin and laminated seams of finer texture. 

 This laminated matrix preponderates towards the base. On 

 the west side of the line, the beds are only overlaid by boulder 

 clay, but on the north-east face, they are partly covered by 

 basalt ; and a dyke penetrates them diagonally from east to 

 west. The quarry on this side extends for about 100 yards, 

 and the ores become much more compact, and are quarried in 

 larger blocks. 



