SC/EXCE-GOSS//\ 



287 



I sought. It was about twelve feel above the 

 path, hidden under tussocks of grass. The indi- 

 viduals were of all agesand very vigorous. Hen; the 

 altitude was about 1 ,2")() feet .().]). 1 found another 

 flourishing colony on the hanks of an interinittent 

 watercourse above Lovers' Leap, Asliwood Dale, not 

 a mile out of Buxton. The snails were crawling on ' 

 the underside of leaves of meadowsweet, dock, and 

 potentilla. One specimen, young and recently 

 dead, occurred on the cliff to the south of the 

 stream-course. By the banks of the stream I 

 •counted quite three dozen in about fifty feet. The 

 location was about !)50 feet O.D., and the superior 

 size and better appearance of the colony may be 

 attributed to greater abundance of food and more 

 favourable general conditions. In no instance 

 here had the periostracum been worn or dried off 

 the shell. The animals were well grown and the 

 shells very beautiful and glossy. Two varieties 

 ■occurred, one dark, the other albino. I found traces 

 also, alive and dead, of H. arbuston/m on the cliff- 

 sides of Ashwood Dale, south of Lovers' Leap. 

 None of the colonies were scattered over a large 

 area, so far as I was able to judge. In Derbyshire, as 

 elsewhere, the species is limited and local in distri- 

 bution.- (Rev.) R. Ashington Bullen, F.L.$.,F.G.S. 



Scientific Investigation of Mollusca. — A 

 Committee, consisting of Messrs. J. R. B. Mase- 

 field, F. Taylor, R. J. Welch, and A. E. Boycott, 

 has been appointed by the Council of the Con- 

 chological Society of Great Britain and Ireland 

 for the purpose of conducting a collective in- 

 vestigation of phenomena connected with the 

 variation and life-history of British Land and 

 Freshwater Mollusca. The object of the investiga- 

 tion is to inquire, by collecting the results of the 

 individual experience of many naturalists, into 

 points liable to general uncertainty and to local or 

 other variation, and into the diffusion and dispersal 

 of species. A certain small number of subjects for 

 investigation will be published each year, and it is 

 hoped that an abundance of replies will be received, 

 so that the results may be thoroughly representative. 

 The following five subjects have been selected for 

 1901 : — (1) How far is the smell of garlic con- 

 stantly associated with Vitrea alliarial Under 

 what circumstances and at what seasons of the 

 year is it most noticeable ? Does V. alliaria seem 

 to escape destruction by other organisms more than 

 the rest of the genus ? Is the smell of garlic found 

 in other species, and under what circumstances ? 

 (2) Have you in any case found any species or 

 variety of land snail constantly associated with 

 any particular plant ? (3) Is any preference shown 

 by (i) Helix aspersa, (ii) H. rufescens for the 

 neighbourhood of human habitations and build- 

 ings ; if so, what explanation do you consider the 

 most probable? (4) What localities produce the 

 largest specimens of Anodontal Describe the 

 nature of the water, soil, geological formation, etc.. 

 and give the dimensions, and, if possible, weight. 

 (5) In the genus Helix, where not indigenous, 

 when and how were any of the species introduced '? 

 It is desired to put on record so far as possible the 

 date of introduction of any species into any given 

 locality, both from abroad into the British Isles 

 and from one part of the country to another. The 

 locality for which each answer is recorded should he 

 ■carefully given, with any details of geological for- 

 mation, altitude, vegetation, etc., which may seem 

 desirable. Returns should reach me by Septem- 

 ber 1, 11)01.— A. JJ. Boycott, The Granae, Hereford. 





GEOLOGY 



.,'T, 





CONDUCTED BY EDWARD A. MARTIN, I'.CS. 



Columnar Structure in Clay-slate. — An 



interesting exhibit at a recent meeting of the 

 Geological Society was a piece of clay-slate, in 

 which columnar structure had been produced 

 through being subjected to the heat arising from 

 the spontaneous combustion of the waste-heap in 

 which it was exposed. The specimen came from 

 Shipley Colliery, Derbv, and was exhibited bv the 

 Rev. J. M. Mello, M.A. 



New Record from the Kellaway Sands.— 

 Mr. Thomas Sheppard, F.G.S., has unearthed from 

 the western slope of Mill Hill, Brough, Yorks, 

 some interesting remains of Crypitoeleidus from the 

 Kellaway Sands, a saurian hitherto unrecorded 

 from rocks older than the Oxford Clay. 'I he re- 

 mains are highly ferruginous, and, being imbedded 

 in a soft sandy deposit, they have been excavated 

 from the matrix with but little damage to the 

 specimens. Twenty-five portions of the animal 

 were submitted to Mr. E. T. Newton, F.R.S.. who 

 identified them. Mr. Sheppard records his find in 

 the " Geological Magazine." 



The Corallian Rocks of St. Ives and 

 Elsworth. — The Elsworth Rock, resting imme- 

 diately upon the Oxford Clay, is identified bv Air. 

 C. B.'Wedd, F.G.S., with the St. Ives Rock of 

 Huntingdonshire. In a paper which he read before 

 the Geological Society, he records tracing the 

 rock at various spots, although, owing to an area 

 of fen intervening, he was unable to follow the 

 actual connection between the two named. The 

 Elsworth Rock, where it has been identified, is 

 bounded on the west by the Oxford Clay and on 

 the east by the Ampthill Clay. The two rocks are 

 considered identical in consequence of the simi- 

 larity of consistency, the absence of any other rock- 

 bed, the dip of the strata, and the presence of the 

 Ampthill Clay above. 



Cleavage of Slates and Schists. — We have 

 received a pamphlet, reprinted from the " Proceed- 

 ings " of the Liverpool Geological Society, dealing 

 with analyses of various slates and schists from 

 North Wales, by T. Mellard Reade, F.G.S., and 

 Philip Holland, F.I.C. Amongst other things, 

 they wished to ascertain upon what composition or 

 causes the perfection of slat}" cleavage depends. 

 They conclude: "At all events it seems pretty 

 clear that slaty cleavage is not alone a mechanical 

 effect. That is to say, mere pressure and shearing- 

 will not produce of themselves true slaty cleavage, 

 unless accompanied by chemical action within the 

 material itself of which the slate is in proers- <<\ 

 being formed." As regards the strength and 

 durability of slates they find: "As a matter of 

 experience we may say that, as regards Welsh 

 slates, the finer varieties split thinner and truer, 

 but the granular are the strongest and most last- 

 ing." The analyses contained in the pamphlet, 

 together with other useful economic information 

 therein, give it a high technical value. 



