HABDWICKE'S SCIENCE-GOSSIP. 



223 



important, and add greatly to the fertility and value t 

 of the islands, as they stop the water from percola- 

 ting downwards through the limestone, and bring it 

 out in lines of beautiful clear springs, usually at the 

 base of the cliffs or steps, the clayey beds having 

 in a great measure induced the former denudation. 



An interesting feature to be observed in these 

 islands is the marine denudation by the Atlantic on 

 the western sides of the islands, as there the sea 

 yearly quarries large blocks and hurls them up on 

 to the surface of the cliffs, forming a rampart that 

 has been called by Prof. King, of the Queen's Col- 

 lege, Galway, " the Block Beach." This beach in 

 one place, in Inishmaan, is on a cliff 170 feet high, 

 and the largest block moved by the sea that was 

 measured was 30 by 15 by 4- feet. On the south- 

 east coast of Inishmaan, the block beach is pecu- 

 liar; for while elsewhere the blocks in the beach are 

 yearly rolled and tossed about, here for years they 

 have not been disturbed ; showing that since the 

 beach was piled up, the set of the tide and waves 

 has altered. In connection with the cliff of the 

 west coast are " puffing-holes." These are due to 



Fig. 126. Puffing-hole. 



the sea-quarry-cut caves along dykes of fault-rock, 

 while subsequently loose portions of the roofs fall 

 in, leaving a funnel (a, fig. 126), When a huge wave 

 comes in, it compresses the air into the extremity 

 of the cave {b), which acts as an elastic cushion and 

 forces the water up through the funnel, often to a 

 considerable height. 



On Inishmore we have an example how the drift 

 of the wind changes. Ages ago the tract south of 

 Killeany Bay was cultivated and inhabited, while 

 subsequently all traces of its former inhabitants 

 were buried by iEolian sands. Now, of late years, 

 the drift of the sands is to the south-west into 

 Gregory's Sound, and the old houses and field are 

 being again exposed, as recorded by the Rev. W. 

 Kilbride. Formerly Gregory's Sound was so rocky 

 and rough, that it was impossible to fish in it ; now 

 this is not the case, as it has a deep sandy bottom. 



Scattered over the surface of the crags of Aran, 

 but especially on Inishmore, are numerous erratic 

 blocks, many of them carboniferous sandstone, 

 evidently the remains of the sheet of boulder-clay 

 drift that once covered most, if not all, of the 



island. These blocks stand on short pedestals, as 

 they have preserved the rock under tbem, while 

 the surrounding surface has been more or less 

 weathered away. As no carboniferous sandstone can 

 be found in the neighbourhood of Galway Bay (al- 

 though probably it formerly existed as shore-beds 

 of the carboniferous sea bounding the granitic rocks 

 of Hiarconnaught), they are called "Connemara 

 stones," and have given rise to the following legend. 

 On the hills called Slieve Moidaun, in Hiarcon- 

 naught, lived a giant, from whom they have received 

 their present name, while a second, whose name is 

 now forgotten, lived on Inishmore. They for a long 

 time were on friendly terms, but at last they fell 

 out, and amused themselves by pelting one another 

 with stones, the Aranite throwing Aran stones into 

 Hiarconnaught, and the Hiarconnaughtite returning 

 in their place stones from his country. Unfor- 

 tunately for the veracity of the legend, there are no 

 carboniferous sandstones in this portion of Hiar- 

 connaught, neither are the boulders of limestone* 

 said to have been hurled into it, to be found. The 

 pedestals under the erratics are accounted for by 

 the giant and his family using the blocks as seats, 

 and wearing away the rock around them with their 

 feet. 



ZOOLOGICAL NOTES. 



BoATFLIES. 



I HAVE often noticed on former occasions the 

 so und made by Notonecta knocking against the 

 sides of aquariums, and this sound was quite dif- 

 ferent, answering more nearly to the stridulation 

 made by grasshoppers or crickets. My aquarium 

 is a heavy wooden one with thick plate-glass sides, 

 and has no ring in it like a bell-glass. I also noticed 

 that the boatfly only emitted the sound when at 

 rest, and the sound only commenced when the 

 insect began to work its anterior feet across its 

 proboscis, and ceased when it stopped that motion. 

 On many occasions the boatfly was one or two 

 inches from the glass side. 



Capuella Acanthifera. 



I dredged two, male and female, of these very 

 strange crustaceans for the first time lately, and 

 should be glad for a little more information about 

 their life-history than is given in Bate and West- 

 wood. Their movements are very remarkable. 

 Holding firmly on by its hinder legs to a frond of 

 seaweed, the Caprella waves its antennae to and 

 fro with a sort of bowing motion, similar to the 

 Mantis, and presumably for the same purpose. The 

 male is bright in colour, yellowish streaked with 

 scarlet, while the female is of a dirty white, the 

 only colour being a little red in rings on the 

 antennae. 



