ISO 



HARDWICKE'S SCIENCE-GOSSIP. 



the group of the Hebrides. Heynish in Tiree is 

 500 feet high, and has many large perched blocks 

 on its top. These blocks are of gneiss, and the 

 author thought they came from the north-west. The 

 Barra islands are described as rocky, aud resembling 

 the hill-tops of a submerged land. All ice-marks 

 found by the author seemed to him to come from 

 the north aud west. He thought that the final 

 grinding was given by floating ice when the land 

 •was more submerged than at present. At Castle 

 Bay, in Barra, the author observed well-preserved 

 glacial striae at the sea-level in a direction from 

 N.N.W. The whole island is glaciated and strewn 

 with perched blocks. Glacial indications were also 

 observed in South Uist, Beuberula, and Skye ; and 

 the author stated that, on the whole, he was inclined 

 to think that the last glacial period was marine, and 

 that heavy ice came in from the ocean, the local con- 

 ditions being like those of Labrador. Mr. Campbell 

 regarded most of the lake-basins of the Hebrides 

 as formed by ice-actioo, and considered that the ice 

 by -which those islands were glaciated eame from 

 Greenland. 



EossiL Man. — The American naturalists have 

 lately been devoting further attention to the fossil 

 human skeleton of Guadaloupe, and the result of 

 their investigation goes to support the idea that it 

 is one of the Carib race. This admission, however, 

 still allows that it may be of considerable antiquity. 



A LAKGE South African Diamond.— A diamond 

 of the first water, weighing over 2SS carats, has 

 been discovered at Waldeck's Place, Vaal River, 

 South Africa. It measures one inch and an eighth 

 in diameter ; so that it is one of the largest rough 

 diamonds known. Its form is that of an irregular 

 octahedron. 



CiiusTACEAN PooTPRiNTS. — Dr. Dawson has 

 described the occurrence of limuloid crustacean 

 footprints in^the millstone grit beds of Nova Scotia, 

 made by an animal not more thau half an inch in 

 ■width. No other remains of limuloid crustaceans, 

 however, have as yet been found in the carboniferous 

 strata of that coimtry. 



Coal Strata op the United States. — Profes- 

 sor Hitchcock states that the total area of the 

 coal-fields of the United States amounts to 230,659 

 square mQes ; besides those coal strata which belong 

 to other formations than the carboniferous, as for 

 instance, those of Virginia (Triassic), of the terri- 

 tories west of the Missouri river (Cretaceousj, 

 and those in California, Alsska, &c. 



The Origin of Guano. — The deposits of 

 guano are usually supposed to be the excrements of 

 birds. Dr. Habel has investigated this matter 

 microscopically aud chemically, and has found that, 

 after treating the substance with an acid, the in- 



soluble residue is composed of fossil sponges and 

 other marine animals and plants precisely similar in 

 constitution to such as still exist in those seas. The 

 fact that the anchors of ships in the neighbourhood 

 of the guano islands often bring up guano from the 

 bottom of the ocean, is quite in opposition to the 

 prevalent belief. Dr. Habel therefore considers 

 that the deposits of guano must be the result of the 

 accumulation of fossil plants and animals whose 

 organic matter has been transformed into nitro- 

 genous substance, the mineral portion remaining 

 intact. 



NOTES AND GUERIES. 



Can Snails reason ? — Some weeks ago T took 

 a cluster of hybernating Helix aspersa, but finding 

 most of the shells weathered, 1 placed them, along 

 with a dozen others, in a box, to be used as oppor- 

 tunity offered for colonizing with. On the 3rd inst. 

 a thunderstorm occurred here, succeeded by rain. 

 The following morning my snails were all out of the 

 box, and had fixed themselves at different elevations 

 on the yard and house walls. Having collected 

 them together again, I replaced them in the box, 

 and removed it beyond accidental reach of the petti- 

 coats, attributing the displacement of the lid to this 

 cause. In the evening, at dusk, upon inspection of 

 the box, the lid was observed to move, and my at- 

 tention being drawn to the circumstance, 1 watched 

 proceedings. In a few moments the lid was slid, 

 by a series of lateral jerks, until an aperture was 

 made suificiently large for me to watch the animals 

 at work. I then saw some eight snails on the 

 box-side actively enlarging the cavity by inserting 

 their heads therein, and, drawing up their bodies, 

 thrusting the lid towards the other side by means of 

 their shoulders. About the same number were on 

 the lid, backs downwards, engaged on the same ob- 

 ject. Indeed, it must have been those on the lid 

 attempting to thrust their bodies through a small 

 nick caused through the warping of the cover, that 

 first made the breach. Evidently the lid had been 

 displaced the night previous by a like process, and 

 the snails were again anxious for a ratnble. As the 

 efforts of the snails must have been directed simul- 

 taneously at one point, what but the knowledge that 

 it required their united powers exerted in a given 

 direction to accomplish a certain purpose could in- 

 duce them so to act, and how could that knowledge 

 be attained but by a process of reasoning? — H. 

 Gornall. 



New Insect-Net. — I believe the time is a,lmpst 

 gone by when tiie naturalist had to conceal his im- 

 plements from the vulgar eye. I myself have always 

 openly carried my net, &c., wherever I have used 

 them, and have not been in any way annoyed. How- 

 ever, if " J. R. S, C." or any other friend would like 

 to make a net according to my plan, capable of 

 being taken to pieces and joined together again, he 

 may do so in various ways. The steadiest and 

 strongest would be to saw through the bamboo, a 

 little below a a in the drawing, and fix a screw into 

 one part and a socket into the other ; but I recom- 

 mend retaining the original construction. Weight 

 in the ring gives extra inertia to the net, so that it 

 will easily retain the motion given to it ; but the 



