April 27, 1888.] 



SCIENTIFIC NEWS. 



403 



surprising that they have contrived to maintain their in- 

 dependent existence, though probably in gradually 

 diminishing numbers, in the midst of powerful tribes of 

 larger stature ; for all the existing evidence points to 

 their being the descendants of the earliest inhabitants of 

 the continent of which we have any knowledge. Our 

 information about them is, however, at present very 

 scanty, and a fuller investigation into their characters, 

 habits, customs, traditions, and language would well 

 repay the labour spent upon it. This subject the lecturer 

 concluded by recommending to the serious attention of 

 future African explorers. 



ROYAL SOCIETY. 

 At the meeting on April 19th, Mr. C. V. Boys read a 

 paper on the " Radio-Micrometer." The author gave 

 the result of a mathematical investigation made with a 

 view to arrive at the best possible construction of the 

 radio-micrometer, already described by him. At the 

 conclusion of the meeting he showed, in action, an in- 

 strument which he had made, having the best proportions, 

 which was both simple in construction and far more sen- 

 sitive than the one he exhibited on a previous occasion. 



GEOLOGICAL SOCIETY OF LONDON. 

 At the meeting on April nth, Mr. W. T. Blanford, LL.D., 

 F.R.S., President, in the chair, the following communi- 

 cations were read : — 



I. "On the Lower Beds of the Upper Cretaceous 

 Series in Lincolnshire and Yorkshire." By W. Hill, 

 Esq., F.G.S. 



The red chalk which forms the basement-bed of the 

 Upper Cretaceous in Lincolnshire and Yorkshire is a 

 continuation of the Hunstanton limestone. Its thickness 

 increases in South Lincolnshire, to thin away again in the 

 north of that county ; but it again increases north of the 

 Humber for a while. Near its most north-westerly 

 exposure on the Yorkshire Wolds the red colour is lost ; 

 but Inoccramus sttlcatus and Bclcinnttcs minimus are 

 found in a dirty yellow-coloured material of trifling thick- 

 ness. Eastwards it regains its red colour and'thickness, so 

 as to be upwards of thirty feet at Speeton, where also it 

 is less calcareous. This section was described in detail, 

 and the results compared with those of other writers. 

 The author speculated upon the probable limits of the 

 Upper Cretaceous sea at this period on evidence mainly 

 based upon the amount of matter of inorganic origin. 

 He noted that Ant. inlcrntptits has been found at With- 

 call, Am. rostratus at South Cave, and Am. auritus (?) at 

 Wharram Grange. 



The base of the Chalk Marl through Lincolnshire con- 

 tinues to be marked by a bed of compact limestone, which 

 is the representative of the" sponge-bed "of Hunstanton. 

 This can also be traced in Yorkshire as far as the north- 

 western extremity of the Wolds. Above this a few feet 

 of grey gritty chalk retain the character of the " Inoccra- 

 mus-h&A " throughout the area above mentioned. At 

 the north-western extremity of the Wolds the main mass 

 of the Chalk Marl has diminished in thickness, but more 

 than recovers this at Speeton, where, according to the 

 ■chemical and microscopical evidence, there is a complete 

 passage from the "Gault" to the " Chalk Marl." The 

 peculiar development of the latter at Speeton was very 

 fully described. No bed, such as the Cambridge Greensand 

 or the Chloritic Marl, can be taken as a line of separation. 



Throughout Lincolnshire and Yorkshire certain courses 



of grey-coloured chalk are recognisable on the horizon 

 of the Totternhoe Stone : these are known collectively 

 as the " Grey bed." Much comminuted shell and numer- 

 ous Pectens characterise this bed, which is faintly recog- 

 nisable even at Speeton. The " Grey bed " determines 

 the upper limit of the Chalk Marl. The equivalents of 

 the Grey Chalk vary less in thickness throughout the 

 area than those already described. Certain lithological 

 characters, which first begin to manifest themselves in 

 the marly beds just above the Totternhoe Stone in Nor- 

 folk, become greatly developed in South Lincolnshire, 

 and throughout that county, as in Norfolk, the grey 

 chalk is usually of a marly nature. In Lincolnshire 

 there is much red colouration on this horizon. The 

 occurrence oi Belemnitclla plena in Lincolnshire has been 

 recognised. The band of bluish black clayey material in 

 which it occurs at Barton continues throughout Yorkshire, 

 but no Belemnite has yet been found. Allusion was 

 made to the characteristic features towards the base of 

 the Middle Chalk. Lists of fossils were given, and a 

 new species of Holaskr (H. roiitndiis) was described. 

 Numerous chemical analyses and microscopic details of 

 structure were also given. 



2. "On the Cae-Gwyn Cave, North Wales." By Henry 

 Hicks, M.D., F.R.S., F.G.S,, with an Appendix by C. E. 

 De Ranee, Esq., F.G.S. 



The author gave an account of the exploration of the 

 cavern during the latter part of 1885, and during 1886-7. 

 He considered that the results obtained during that time 

 proved conclusively that there was no foundation for *he 

 views of those who contended that the drift which 

 covered over the entrance and extended into the cavern 

 was remanie, but they proved that the deposits which 

 lay over the bone-earth were in situ, and were identical 

 with the normal glacial deposits of the area. These de- 

 posits had once extended continuously across the valley, 

 and the cavern (400 ft. above Ordnance Datum) had con- 

 sequently been completely buried beneath them. 



The cave must have been occupied by animals during 

 the formation of the bone-earth before any of the glacial 

 deposits now found there had accumulated, and a thick 

 floor of stalagmite had covered this " earth " before the 

 cavern had been subjected to water-action. This action 

 had broken up the floor, and completely resorted the 

 materials, and added sandy and gravelly material to the 

 deposits ; this sand and gravel had been examined by 

 Professor Boyd Dawkius, who found that it agreed in 

 every particular with the glacial sand and gravel occur- 

 ring in the valley a little way above. The large lime- 

 stone blocks in the cavern had also been evidently 

 disturbed by water- action ; they were invariably found 

 in the lowest deposits, and were covered over by lami- 

 nated clay, sand, and gravels. The author considered 

 it certain that the caverns had been completely filled 

 with these materials, and in the case of the Cae-Gwyn 

 Cave they appeared to have been conveyed mainly 

 through the entrance recently discovered under the drift. 

 The stratification at this entrance was so marked, and 

 could be traced so continuously inwards over the bone- 

 earth, that there could be no doubt that this was the 

 main entrance. There was not the slightest evidence 

 that any portion of the material had been conveyed in 

 through a swallow-hole, and the conditions witnessed 

 throughout were such as to preclude any such idea. 



The author quoted a report by Dr. Geikie, who con- 

 sidered that the wall of the cavern had given way, but 



