HARDWICKE'S SCIENCE-GOSSIP. 



117 



Geology oe Clevedon. — I am writing to you 

 in hopes that some of the readers of Science- 

 Gossip may be induced to turn a little attention 

 to the geology of Clevedon, Somerset, which is 

 certainly interesting, and the town and neighbour- 

 hood are very lovely, and would well repay a visit, 

 though the place is comparatively little known. I 

 feel interested in the question as to whether the 

 Dolomitic conglomerate which flanks this coast and 

 that of Portshead, resting on or abutting against 

 the Carboniferous limestone, belongs to the lower 

 Permian or upper Triassic system. It is a question 

 which, I venture to thiuk, might be more easily 

 solved here than near Bristol, and I should like to 

 have the opinion of some geologists who have ex- 

 amined the strata here, as it seems to me im- 

 possible to come to any other conclusion than that 

 it belongs to the Permian system, and the Clevedon 

 " Guide-book" calls it "Magnesian Conglomerate," 

 on the authority of a geologist. The Magnesian 

 limestone, which is quarried near the sea, for build- 

 ing, lies above the Conglomerate, the two gradually 

 passing into each other ; and in a new section I 

 was examining the other day, lower down in the 

 cliffs, a dull purplish marl is exposed, interstratified 

 with thin layers of Conglomerate : surely this must 

 be Permian marl ? The Keuper marl of Redland, 

 Bristol, is about equally hard, but of a brighter 

 colour, and has not the blood-red tinge I sometimes 

 see in the other. I have found imperfect fossils 

 occasionally, principally of Magnesian lime- 

 stone and Conglomerate, but they probably, from 

 the situation of their strata, mostly belong to the 

 Carboniferous limestone. The Conglomerate rock 

 is sparkling, and often coloured green, as if from the 

 presence of copper, and both it and the Magnesian 

 limestone above it have drusy cavities containing 

 transparent crystals. I do not think that the strata 

 of which I am writing are marked at all in Saunders' 

 "Maps of the Bristol Coal-field," which may be 

 seen at the Bristol Museum. The Old Red sand- 

 stone is known to form the basement along the 

 coast-line in this neighbourhood, the Conglomerate 

 cliffs resting on it. Should any of your readers be 

 able to throw light on the difficulty, I should feel 

 very much obliged by their replying in Science- 

 Gossip.— ff. L. G. a, 



Discovery of Fokaminifera, &c., in the 

 Boulder-Clays of Cheshire. — A paper on this 

 subject has just been read before the London 

 Geological Society, by W. Shone, jun. The author 

 described the occurrence of Foraminifera entomo- 

 straca, and some other small organic bodies, in the 

 boulder-clay at Newton by Chester, and at Dawpool. 

 They were found partly in the interior of specimens 

 of Turritella terebra, and partly free in the boulder- 

 clay ; but those obtained from the Turritel^cB were 

 in better condition than the others. The Forami- 



nifera generally agree precisely with those found in 

 the tidal parts of the river Dee. Mr. Shone stated 

 further that the Turritellw containing Foramini- 

 fera are filled with a fine greyish-white sand, in 

 which the minute fossils abound, and he discussed 

 the probable conditions under which the deposit 

 containing them had been formed. Mr. Gwyn 

 Jeffreys said that the Foraminifera sent by Mr. 

 Shone are exactly the same as those found on the 

 shores of England, Wales, and Scotland. The 

 Foraminifera inhabit the edge of high water, and 

 would naturally fill any shells that might be lying 

 on the shore about that line. They might have 

 been transported by ground-ice. Mr. Jeffreys 

 remarked that we know comparatively little of the 

 Arctic fauna at present, and that it was highly de- 

 sirable that an expedition should be sent to investi- 

 gate the marine fauna of high northern latitudes. 

 Prof. T. Rupert Jones stated that the Rotaliae are 

 identical all round the coasts, those from different 

 localities presenting different characters, as may be 

 plainly seen in the Rotalia Beccarii of the Adriatic 

 and of the English coasts. Various circumstances 

 seem to act in changing the forms, especially 

 whether the animals have inhabited deep or shallow 

 water, or water more or less fresh. The Globigerince 

 have thicker shells in deep than in shallow water. 

 When ill-nourished, Foraminifera alter in the style 

 of their outline. 



NOTES AND aUERIES. 



MoLLTJSCAN Threads. — The recent interesting 

 article in Science - Gossip upon " Molluscan 

 Threads," induces me to add some little information 

 that is new to the author of that paper, as well as 

 unknown to most observers, I find. The author of 

 "Molluscan Threads" states, at page'i50, second 

 column, "Slugs often suspend themselves by a 

 thread, but do not use it as a means of ascents 

 That they can and do sometimes so use it the fol- 

 lowing will show, but that they are in the habit of 

 doing so I cannot assert, though I believe it to be 

 the fact that they do. I have frequently made the 

 common Limax arborum suspend itself by putting 

 a branch of ash with a small cross branch tjent very 

 slightly downwards into a flower-pot. I placed the 

 slug upon this cross branch with its head towards 

 the point. It immediately crawled to the point, 

 over which it gradually slid, holding on by its tail, 

 which at last became detached, and then the thread, 

 which is merely a slimy secretion, is formed, and 

 continues to be formed by the weight of the mollusc 

 drawing it off the body. 1 believe the act to be 

 entirely involuntary, for, from the time the slug 

 reaches the end of the branch until its descent is 

 finished, it is looking, as it were, for fresh footing, 

 and it can keep its body not quite horizontal but 

 oblique to the thread. If, when it has descended 

 some distance, say eight or ten inches, the finger, 

 moistened with a slightly saline solution— say 

 saliva— is applied to it beneath, it deliberately turns 

 itself up in a spiral form, and enclosing the thread 

 in its mantle, reascends by a steady motion, the 



