June 20, 1895] 



NATURE 



191 



the hope that Dr. llaviland would shortly publish the very 

 valuable observations he had made. In the case of a species of 

 fungus Termite, Dr. Haviland had found that the community 

 had replaced a king and queen by normal, not by neoteinic 

 forms. — Mr. McLachian, K.K.S., exhibited examples of the female 

 of Pyrr/iosoma niiiiiiim, Harris, having the abdomen incrusted 

 with whitish mud through ovipositing in a ditch in which the water 

 W.1S nearly all dried up. He had noticed the same thing in other 

 species of Agrionidce. — Mr. Koland Trimen, F.R..S., exhibited 

 some specimens of "Honey" .\nts, discovered at Estcourt, in 

 Natal, about a year ago, by Mr. J. M. Hutchinson. The species 

 has not been identified, but isquite difierent (riiw\ Myrmecocystus 

 and Camponottis — the genera which have long been distinguished 

 as containing species, some of whose workers are employed as 

 living honey-pots for the benefit of the community. The speci- 

 mens exhibited included six "globulars" — touse Mr. McCook's 

 term in regard to the American species, Myrmeiocystiis liortus- 

 diorum — all with the abdomen enormously distended with 

 nectar ; but other examples presented to the South African 

 Museum by Mr. Hutchinson comprised various individuals 

 exhibiting different gradations of distension, thus indicating 

 that the condition of absolute repletion is arrived at gradually, 

 and may possibly be reached by some few only of those indi- 

 viduals who feed, or are fed, up for the purpose. Certainly, in 

 the nests examined by Mr. Hutchinson, in Natal, the number 

 of ''globulars" was very small in proportion to the population 

 of ordinary workers ; and it is somewhat difficult to understand 

 of what particular value as a food reserve so very small a quan- 

 tity of nectar so exceptionally stored can be. Mr. Trimen 

 added that while the occurrence of" Honey" Ants in Southern, 

 North America, South Australia, and he believed also in India, 

 was well known, the Natal species now exhibited was the 

 first .-\frican one that had come under his notice. — Dr. Sharp 

 exhibited a series of Coleoptera, to illustrate variation in size. — 

 Herr Brunner von Wattenwyl made a communication informing 

 the Society that a most unfortunate error had crept into the 

 table of genera in his .Monograph of Psiudophyllidcs ; on page 9, 

 line I, and on page 13, line 37, instead of " mesonotum " should 

 be read " mesosternum." 



Geological Society, June 5.— W. H. Iludleston, F.R.S., 

 A'ice-I'resident, in the chair. — On a well-marked horizon of 

 Radioliirian rocks in the Lower Culm Measures of Devon, Corn- 

 wall, and West Somerset, by Dr. (I. J. Hindc and Howard 

 Fox. .In the Lower Culm Measures the basal I'osidoiiomya-hed?, 

 and the \Vaddon Hartfjn beds with Goiiialiles spiralis consist of 

 fine shales with thin limestones, and above these are the beds 

 which form the subject of the present paper. The Upper Culm 

 Measures consist of conglomerates, grits, sandstones, and .shales, 

 with occasional bedsof culm. There is evidence of the partial 

 denudation of the radiolarian rocks during the accumulation of 

 the Upper Culm beds, as indicated by the presence of pebbles of 

 the former in the latter. The radiolarian beds consist ofa series 

 of organic siliceous rocks — some ofa very hard cherty character, 

 others platy, and yet others of soft incoherent shales. The term 

 "grits," which has been used in connection with these beds, is 

 a misnomer ; there are beds which are sujierficially like fine 

 grits, but they are found to be radiolarian deposits. .\t present 

 there are not sufficient data for estimating the thickness of the 

 radiolarian deposits ; but they are probably some hundreds of 

 feet thick, though the whole does not consist of beds of organic 

 origin. In a quarry in the Launceston district 50 feet of radio- 

 larian cherty rock are seen without admixture of shale. .\ 

 <letailed description of the lithological characters of the rocks of 

 the .series was given, and analyses by Mr. J. Hort Player: a 

 marked feature of their compo.sition is the very general absence 

 of carbonate of lime. The microscopic characters of the rocks 

 were also described, and the small amount of detrital matter in 

 the beds of the series was noted. The fossils tend to confirm 

 the view that the Lower Culm .Mea.sures are the deep-vv.ater 

 eijuivalents of the carboniferotis limestone in other parts of the 

 British Isles, and not shallow-water representatives of deeper 

 bells occurring to the north, as was formerly supposed. In con- 

 nection with this it was noted that the deep-sea character of the 

 Lower Culm of (lermany, which corresponds with our Lower 

 Culm Measures, was maintained by Dr. Hobajifel even before 

 the discovery of radiolaria in the Leds of Kieselschiefer furnished 

 such strong evidence in support of this view.— The geology of 

 Mount" Kuwenzori a'nd simie ailioining regions of Equatorial 

 Africa,- by C.F: Scott-i:ili6t and Dr. J. \V. Gregory. Kuwen- 

 zori is- a- nu«imain between the Albert and Albert Edward 



NO. 1338, VOL. 52] 



Nyanzas. Topographically it is a narrow ridge which extends 

 for about 50 miles in a direction from north-north-east to south- 

 south-west. Its summit .attains a height of 16,500 feet. The 

 western slope is at an angle of 22° ; the eastern slope at about 

 one of 4^ The authors described sections across the ridge at 

 right angles to its trend. These showed that Kuwenzori is not 

 volcanic, nor is it a sini])le massif of diorite. Epidiorite occurs 

 only as banded sheets in the schists on the flanks of the moun- 

 tain, and is not the central rock of the ridge. The strike of the 

 flanking schists seems to run concentrically round the ridge as 

 though the central rock were intrusive into them. The highest 

 rock collected, a coarse-grained granite or granitoid gneiss, may 

 be an intrusive igneous rock, but it may be part of the old 

 Archaean series faulted up ; there is nothing in its microscopical 

 characters to separate it from the Archaean rocks, and the 

 authors thought it probable that this rock was raised into its 

 present position by faulting. In this case Kuwenzori is simply 

 composed of an orographic block or " scholl," which was at one 

 time probably part of a w ide plateau of Archaean rocks. There 

 is abundant evidence of volcanic action around Kuwenzori, for 

 the plains, especially to the east and south-east, are studded 

 w ith small volcanic cones, arranged on lines which radiate from 

 Kuwenzori. Evidence points to the former occupation of the 

 Xyaniwamba, Mubuku, and Batagu valleys by glaciers, roches 

 iiioiitoinu'es of tyjjical character having been noted in the two 

 former valleys. The country round Kuwenzori consists of 

 rocks which may be conveniently grouped into two series — one 

 composed of gneisses and schists, and the other of non-foliated 

 sediments. The former (the .^rchaen series) are of the type that 

 has an enormous extension in Equatorial Africa, and forms the 

 main plateau on which all the sediments and volcanic rocks 

 have been deposited. The sedimentary rocks are probably 

 Paleozoic, possibly pre-carlioniferous, but in the absence of 

 fossils it would be unsafe to go beyond this statement. — On 

 overthrusts of tertiary date in Dorset, by A. Strahan. The re- 

 sults given in this paper were obtained during a re-survey of 

 South Dorset on the 6-inch scale. The disturbances can be 

 divided into two groups — the one being mainly of Miocene date, 

 and the other of intra-cretaceous (between Wealden and C.ault) 

 age. The former includes the Isle of Purbeck fold (which is 

 the continuation of the Isle of Wight disturbance), the King- 

 stead fold, the Chaldon and Ridgeway disturbances, and the 

 Litton Cheney fault. In the latter are placed the anticline of 

 Osmington Mill, the syncline of Upton, and a part of the anti- 

 cline of Chaldon ; farther west the Broadw-ay anticline and Up- 

 way syncline, a fault at Abbotsbury, and many other folds come 

 into the same group. These earlier movements led to the well- 

 known unconformity at the base of the Upper Cretaceous rocks. 



W Linnean Society, June 6. — Mr. W. Percy Sladen, Vice- 

 President, in the chair. — The minutes of the last meeting having 

 been read and confirmed, the Chairman, on behalf of the Presi- 

 dent, declared the following to be \'ice-Presidents : — Messrs. 

 T. G. Baker, F. Crisp, A. Lister, and W. P. Sladen. Mr. B. 

 B. Woodward was elected a Fellow. — Mr. M. Buysnian, who 

 has laboured for many years to establish a garden at .Middleburg 

 for economic plants, exhibited specimens to show the excellence 

 and completeness of his preparations. — On behalf of Mr. T. J. 

 Mann, who had lately returned from Ceylon, Mr. Harting 

 exhibited specimens of a butterfly, Calophaga galena, Felder, 

 which had been observed migrating in thousands across the 

 northern part of the island during March and April last, 

 in a direction from north-east to south-west. The move- 

 ment commenced about 7 a.m. and lasted until noon, 

 when it decreased, and was resumed in the afternoon for 

 another two hours. Mr. Harting referred to the remarks on this 

 subject made by Sir J. Emerson Tennent ("Nat. Hist.," 

 Ceylon, 1861, p. 404, note) to the observations of Darwin 

 on the countless myriads of butterflies met with at sea some 

 miles off the mouth of the Plata, and to a paper by Mr. 

 R. McLachian on the migratory habits of Vanessa tardiii 

 {Enlom. Mo. Mag., xvi. p. 49). He did not think that the 

 movement was analogous to the migration of birds which 

 migrated in opposite directions in spring and autumn, for the 

 insects moved only in one direction, and did not return, vast 

 numbers perishing en route. The phenomenon rather resembleil 

 what had been observed in the case of lemmings, locusts, and 

 dragon-flies (Weissenborn, Mag. Nat. Hist., n.s., vol. iii. 

 p. 516), and might be explained as a sudden exodus from' the 

 birthplace, leading to a compensating reduction of ttiCL si^ecies 

 after a season exceptionally favourable to its increase. "" 



His 



