April 19, 1877J 



Europe and Asia 



Africa 



North America . 



South America . 



Australia, &c. 



NATURE 



543 



Towards 



Towards Behring's Towards 



Greenwich. Strait. Yucatan, 



Mile. Mile. Mile 



— 587 I99-4 



— 269 — 



152 

 199 



35-1 



— 302 — 



Towards 



Rangoon. 



Mile. 



17 

 105-5 



30.2 



The power of Europe and Asia in moving the pole is partly 

 due to the extension of this continent along the parallel of 45°, 

 which is the most effective latitude. The actual effect jiroduced 

 by Europe and Asia was not much less than that of our ima- 

 ginary continent (Note I. ), occupying one eighth part of the 

 surface of the globe. 



The foregoing results are positive, and the motions of the pole 

 indicated must have actually occurred when the existing con- 

 tinents were formed. But simultaneously with these elevations 

 depressions must have gone on elsewhere, continents disappear- 

 ing beneath the sea and sinking to tlie zero plane, while other 

 continents were rising. It is to be noticed that although the 

 excavation of the sea-bottom to its present depth below the zero 

 plane, corrected for the weight of the ocean, produces no mo- 

 tion in the pole, yet that the depression of a continent down to 

 the zero plane produces a motion of pole equal and opposite to 

 that produced by its elevation. I have calculated the hypo- 

 thetical effects of the depression of imaginary continents occu- 

 pying the sites of the present Pacific Ocean, with the following 

 results : — 



North Pacific Ocean (depressed). 



Towards Yucatan ... ... ... 3*4 miles. 



Towards Behring's Straits ... ... 250*6 „ 



South Pacific Ocean (depressed). 



Towards Rangoon I56'2 miles. 



Towards Greenwich 238 "2 ,, 



The total effect of aj continent equal to the North Pacific 

 would be — 



Vx" + Y"^ = 250*6 miles. 



I = tan (<?.), <^ 



0° 47' E. of 180°. 



The total effect of a continent equal to the South Pacific 

 Ocean would be — 



VX^ + Y2 

 X 

 Y 



201 8 miles. 



tan (<|)), </) = 23° 17' E. of Greenwich. 



Geological Society, March 21. — Prof. P. Martin Duncan, 

 F.R.S., president, in the chair. — William B. Coltman, William 

 James Grimshaw, and Alexander Ross were elected Fellows of 

 the Society. — The following communications were read : — On 

 the strata and their fossil contents between the Borrowdale series 

 of the North of England and the Coniston flags, by Prof, 

 Robert Harkness, F.R.S., Cork, and H. AUeyne Nicholson, 

 F. R.S.E., Proftssor in St. Andrew's. The object of this paper 

 was the investigation of the strata between the great volcanic 

 series of the Lake-district, the Borrowdale rocks, and the sedi- 

 mentary rocks called Coniston Flags by Prof. Sedgwick. The 

 Borrowdale series, the Green Slates and Porphyries of Sedgwick, 

 are underlain by the Skiddaw Slates, forming the base of the 

 Silurian series, and equivalent in age to the Arenig rocks of 

 Wales, according to their fossil contents. The Borrowdale rocks 

 consist of ashes and breccias, alternating with ancient lavas, and 

 are partly subaerial, partly submarine. They contain no fussils 

 except in a band of calcareous ashes near the summit of the 

 group, which is followed by the Coniston Limestone, with or 

 without the intervention of a bed of trap. The fossils are of 

 Bala types. Sometimes this band is recognisable, with no traces 

 of fossils except cavities filled with peroxide of iron. The 

 authors regard this as proving the prevalence of volcanic activity 

 in the Lake District up to the later portion of the Bala period. 

 The deposits specially discussed in the paper sent lie, apparently 

 quite conformably, upon the Borrowdale rocks, and are grouped 

 by the authors as follows, in ascending order: — (i) Dufton 

 Shales ; (2) Coniston Limestones and Shales ; (3) Graptolitic 

 Mudstones or Skelgill beds ; (4) Knock b;ds. The " Daftcn 

 Shales" are a well-marked but locally distributed group of 

 muddy deposits, especially well developed in the Silurian area 

 underlying the cross Fell range, where they are seen in four 

 principal exposures, and their thickness probably exceeds 300 



feet. They are richly fossiliferous. The "Coniston Limestone " 

 has long been recognised as the best-defined division of the 

 Lower Silurian rocks of the north of England. The " Grapto- 

 litic Mudstones" overlie the Coniston Limestone, wherever the 

 summit of the latter is to be seen. Besides Graptolites, they 

 contain many other fossils, including Corals, Brachiopods, 

 Cephalopods, and Crustaceans ; and from the consideration of 

 the whole fauna, the authors are led to believe that the position 

 of these deposits must correspond either with the hijjhest beds 

 of the Bala series or with the lower portion of the Llandovery 

 group. The Graptolitic Mudstones are succeeded by the 

 "Knock beds," so called from their great development in Swin- 

 dale Beck, near Knock. Wherever they occur they consist 

 chiefly of pale green, fine-grained slates, very ashy in appearance, 

 and presenting many dendrites, and frequently crystals of cubic 

 pyrites. There is no evidence of unconformity between them 

 and the underlying Mudstones. — On a new area of Upper Cam- 

 brian Rocks in South Shropshire, with the description of a new 

 fauna, by C. Callaway, F.G.S. The purpose of the author was 

 to prove that certain olive, micaceous, thin-bedded shales ex- 

 posed at Shineton, near Cressage, and covering an area of eight 

 miles in length by two in the greatest breadth, which had been 

 mapped as Caradcc in the survey, were of Tremadoc age. They 

 were seen clearly to underlie the Hoar Edge Grit, the lowest 

 beds in the district, with Caradoc fossils ; and no rock distinctly 

 underlying the shales could be detected. The evidence for their 

 age was chiefly palaeontological. With the exception of Asaphus 

 homfrayi, a Tremadoc form, the species are new. Genera such 

 as Olentes, Conocoryphe, OboUlla, and Lins,uleUa suggested a 

 very low horizon, but two Asaphoid forms (though not typical 

 Asaphi) pointed in an opposite direction. Corroborative evi- 

 dence was found in a correlation of the shales at Shineton with 

 the Dictyonema-^^z^ at Pedwardine and Malvern. 



Anthropological Institute, April to.— Mr, John Evans, 

 F.R.S., president, in the chair. — The president exhibited two 

 stone instruments from Sandoway District, North Burmah. — 

 Some flint arrow-heads, scrapers, &c., from Ditchley, Oxon, 

 were exhibited by Capt. Harold Dillon. — A paper on some rude 

 stone monuments in North Wales was read by Mr. A. L. Lewis. 

 The chief point of interest being the existence, hitherto, we 

 believe, unnoticed, of single outlying stones on the north-east of 

 the circle near Penmaunmawr which is thus shown to conform to 

 and to lend further confirmation to the rule found by him to 

 exist generally in British circles of a special reference to the 

 north-east by outlying stones or otherwise. — The director read 

 a p?per by the Rev. W. Ross, F.S.A. Scotland, on some 

 curious coincidences in Celtic and Maori vocabulary. — Papers 

 were also read by the director, on Australian aboriginal lan- 

 guages, traditions, &c., by Messrs. Greenway, McDonald, 

 Rowlay, Malone, and Dr. Creed, communicated by Mr. Wil- 

 liam Ridley, M.A., through the Colonial Office. — Col. .\. Lane 

 Fox, F. R.S., Messrs. Hyde Clarke, Walhouse, Moggridge, 

 Park-Harrison, and the president, took part in the discussion. 



Royal Microscopical Society, April 4. — H. C. Sorby, 

 F.R S., president, in the chair. — The following papers were 

 read : — On the variability of the chlorophyll bands in the spec- 

 trum, by Mr. Thomas Palmer, in which he described the various 

 effects produced by solutions in alcohol, &c., and by treatment 

 with acids and alkalis. — On the mineralogical constitution and 

 microscopical characters of the whetstones of Belgium, by M, 

 I'Abb^ Renard, of Louvain. — On the microscopical character of 

 Krupp's " silicate cotton," by Mr, H. J. Slack, and on the 

 lowtr Silurian lavas of Cumberland, by Mr. Clifcon Ward, in 

 which it was shown that the diflertnce between ancient and 

 modem lavas was not so great as was usually supposed, their 

 actual constituents being very nearly the same, though appa- 

 parently they difftred owing to conditions which had produced 

 metamorphosis in the earlier series. 



Physical Society, March 17. — Prof. G. C. Foster, presi- 

 dent, in the chair. — Mr. W. S. Seaton was elected a member of 

 the society. Mr. Spottiswoode exhibited some experiments on 

 the stratification of the electric discharge in vacuum tubes, and 

 described bis attempts to produce the effects as obtained by Mr. 

 Gassiot and Mr, de la Rue, with batteries of several thousand . 

 cells, by means of the induction coil. An account of his experi- 

 ments has already been given in our pages. — Capt. Abney, R.E., 

 then read a paper on the photographic image, prefacing it by a 

 brief account of the two theories, the chemical and the physical, 

 which are held regarding it. On the former, a molecule of 

 bromide of silver is split up into sub-bromide and bromine, 



