HARUWICKE'S SCIENCE-GOSSIP. 



173 



the south eud of the lake flows the Beagh river, 

 having an overground course for about two miles, 

 when the stream disappears into the limestone rock 

 under a boulder-clay-drift cliff about 70 feet high, 

 the place locally being called "The Caldron." 

 From here the river course can be traced for nearly 

 a mile by breaks in the roof of the subterranean 

 passages, forming marked precipitous hollows, or 

 cavities, known as the "Devil's Punch-bowl," 

 the "Blackweir," the " Ladle," and the " Churn," 

 to " PoUduagh," a cave out of which the water 

 rushes to daylight. 



From PoUduagh northward for about three 

 miles there is an open river to the ruins of Kil- 

 tartan Castle, where it again takes the ground ; 

 however, farther west, in Coole demesne, it appears 

 for a short distance, and eventually flows into Coole 

 Lough, having first mingled its waters with those 

 of another subterranean river that receives the 

 drainage of the northern portion of Slieve-Aughta. 

 From Coole Lough the waters flow underground 

 to Caherglassaun lake, and from thence to the sea 

 at Kinvarra, a large stream appearing through the 

 joints of the limestone in the vicinity of Dungorey 

 Castle. 



Where the Beagh river takes the ground at " The 

 Caldron " it is yearly cutting into a high bank of 

 boulder-clay-drift that contains blocks and frag- 

 ments of sandstone and limestone, all of which dis- 

 appear. The latter may dissolve in the water and 

 thereby be carried off in solution, as the chert which 

 they contain forms an angular gravel in the bed of 

 the stream ; but the sandstone blocks could not be 

 similarly disposed of. Some of the latter, un- 

 doubted! j% are ground up ; for, when the stream is 

 in flood, and the waters, hurrying underground, 

 form a rushing gurgling whirlpool, the blocks can 

 be heard rolling about and grinding against one an- 

 other. This, however, can scarcely account for the 

 disappearance of all, as hundreds of them cotne 

 down each winter ; yet when the water is low during 

 the summer months, only a few of them are to be 

 seen ; therefore it only remains for them to be 

 carried underground. This, when the stream is 

 seen in its summer aspect, would appear impossible, 

 as the water flows on to a filter of blocks and 

 gravel ; but when the fioods arise, these gradually 

 get into motion, until at last all are being whirled 

 round and round, while some possibly find their 

 way into the vent and are carried away in the 

 stream. In favour of this theory it may be pointed 

 out that blocks of sandstone are found in the bed 

 of the subterranean stream at Pollduagli. 



The exit of the river in the vicinity of Kiltartan 

 Castle is remarkable. It is evident that at former 

 periods the water flowed at two higher levels, but 

 in each case, as the subterranean passage increased, 

 they fell into disuse. The highest level is now 

 quite abandoned by this river, and a small stream 



flowing southward into the river occupies it, 

 while the middle level is still used, but only in high 

 floods. If there is an over-supply of water, too 

 much for the lower embouchure, the water rises to 

 the second level, along which it flows to a cavity in 

 the roof of the under-passage, where it finds an 

 exit, and rushes down, forming a whirlpool ; thereby 

 proving that the internal capacity of the passage is 

 greater than its entrance. 



In the country about Gort, as also in many other 

 limestone tracts in Ireland, at the ingress or egress 

 of the subterranean rivers, sheets of water may 

 form, that are locally called " Turloughs ;" or a 

 furlough may exist in a hollow under wnich there 

 is a snbterranean stream, the latter bursting up and 

 overflowing during freshets, forming a sheet of 

 water. Many of the small lakes hereabouts have 

 no surface-outlets, and although they do not become 

 dry in summer, yet are a variety of turlough, a good 

 example being the small lake called Lough Kinlea, 

 about six miles west of Lough Rea. The water in 

 this lake in dry weather lies at the bottom of a 

 deep cup-shaped hollow at least thirty feet 

 lower than the adjacent road, while in floods the 

 surface of the lake reaches or even overflows on to 

 the road ; but, on account of the steepness of the 

 sides of the hollow, the difference between the 

 area of the water in flood and drought is small. 



A remarkable furlough is formed during floods 

 in connection with Coole Lough. During the dry 

 weather the drainage from all sides flows into the 

 lough ; but if a flood arises, the subterranean vents 

 arc insufficient to carry oif the waters ; consequently 

 tliey rise, fill the lough, and overflow to the south, 

 forming an extensive furlough in the hollow adjoin- 

 ing the Newcastle Racecourse. The extent and 

 sudden rise of the floods may be judged from the 

 following :— On the 12th October, 1852, a cricket- 

 match was played on the racecourse of Newcastle, 

 and in the adjacent streams there was scarcely any 

 water ; but in the succeeding week there was rain, 

 and on the 21st of the month the whole of it was 

 covered, in places being over twenty feet deep. The 

 area under water, including the flooded land about 

 Coole Lough, was at least 500 acres. It should, 

 however, be mentioned that this October was the 

 wettest of the seventeen years preceding, the rain- 

 fall being 7'61 inches, while the average was 4'03 

 inches, the other wet years being 1846, 1851, and 

 1853, whose figures respectively were 6"85, 5"35, 

 and 572 inches by the Rev. C. Mayne's rain- 

 gauge at Killaloe ; the rainfall of October, 1SG2, 

 being nearly twice the average of the preceding 

 seventeen years. 



Some of the low-situated lakes and turloughs 

 are afi'ected by the rise and fall of the tide, the 

 rising of the tide damming up the subterranean 

 egress of the fresh water, causing the latter to rise 

 in the lakes or turloughs. In some of these during 



