Dec. 2 2, 1887] 



NATURE 



191 



species of Caucasian Wild Goat. This he proposed to call 

 Capra set'erlzetn, being the C. caucasica of Dinnik, but not of 

 Guldenstaedt. — Sir. Blanford read some critical notes on the 

 nomenclature of Indian Mammals, in which he treated of 

 Micacusferox, Shaw (J/, iilenus, auct., nee Linn.), Af.irus, Cuv. 

 (M. eynomolgus, auct., nee Linn.), M. rhesus, Preshytes thersites 

 Blyth, Senntopil/ieeiis chrysogaster, Fclis bengiilensis, F. jerdoni, 

 Her/>estes Piungo {//. ^riseus, auct., //tr Geoffr.), Vulf>es vulgaris, 

 V. alopex, and the genera Putorms; Mustela, Xantharpyia, 

 Cynonyctais, Hipposiderus, and Phvllorhina. 



Geological Society, December 7. — Prof. J. W. Judd, 

 F. R. S., President, in the chair. — The following communications 

 were read: — A letter from M.M. Secretary of State for the 

 Colonies, inclosing an account of recent discoveries of gold in 

 the Transvaal. — On the age of the altered limestone of Strath, 

 Skye, by Dr. Archibald Geikie, F.R.S. The remarkable 

 alteration of the limestone of Strath into a white saccharoid 

 marble, first described by Macculloch, has hitherto been re- 

 garded as an instance of contact metamorphism in a rock of 

 Liassic age. The various writers who have described the geology 

 of the district have followed Macculloch in classing the whole of 

 the ordinary and altered limestone with the Secondary series of 

 the Inner Hebrides. The author, however, saw reason in 1861 

 to suspect that some part ^f the limestone must be of the age of 

 the Durness Limestone of Sutherland — that is, Lower Silurian ; 

 and he expressed this suspicion in a joint paper by the late Sir 

 R. I. Murchison and himself, published in the eighteenth volume 

 of the Quarterly Journal of the Society. He has recently returned 

 to the subject, and now offers lithological, stratigraphical, and 

 palccontological evidence that the altered limestone is not Lias, 

 but Lower Silurian. In lithological characters the limestone, 

 where not immediately affected by the intrusion of the eruptive 

 rocks, closely resembles the well-known limestones of the west 

 of Sutherland and Rosshire. It is not more altered than 

 Pa!a:ozoic limestones usually are. It contains abundant black 

 chert concretions and nodules, which project from the weathered 

 surfaces of the rock exactly as they do at Durness. These 

 cherts do not occur in any of the undoubted Lias limestones of 

 the shore-sections. The limestone lies in beds, which, however, 

 are not nearly so distinct as those of the Lias, and have none of 

 the interstratifications of dark sandy shale, so conspicuous in 

 the true Liassic series. The stratigraphy of the altered lime- 

 stone likewise marks it off fr.im the Lias. There appears to be 

 a lower group of dark limestones full of black cherts, and a 

 higher group of white limestones with little or no chert, which 

 may be compared with the two lower groups of the Durness 

 Limestone. A further point of connection between the rocks of 

 the two localities is the occurrence of white quartzite in associa- 

 tion with the limestone at several places in Strath, ami of 

 representatives of the well-known "fucoid beds" at Ord, in 

 Bleat. These latter strata form a persistent band between the 

 base of the limestone and the top of the quartzite, whic'i may be 

 traced all the way from the extreme north of Sutherland south- 

 ward into Skye. Palaeontological evidence confirms and com- 

 pletes the proof that the limes' one is of Lower Silurian age. 

 The author has obtained from the limestone of Ben Suardal, 

 near Broadford, a number of fossils which are specifically 

 ilcntical with those in the Durness Limestone, and so closely 

 resemble them in lithological aspect that the whole might be 

 believed to have come from the same crag. Among the fossils 

 are species of Cyclonema, Murchisonia, Maclurea, Orthoceras, 

 and Piloceras. The relations of the limestones containing these 

 fossils to the other rocks were traced by the author. He showed 

 that the Lias rests upon the Silurian limestone with a sti ong un- 

 conformability, and contains at its base a coarse breccia or 

 conglomerate, chiefly composed of pieces of Silurian limestone, 

 with fragments of chert and quartzite. The metamorphism for 

 \yhich Strath has been so long noted is confined to the Silurian 

 limestone, and has been produced by the intrusion of large 

 lx>sses of granophyre (Macculloch's "syenite") belonging to 

 the younger, or Tertiary series of igneous rocks. After the 

 reading of the paper some remarks were made by Mr. Etheridge, 

 Dr. Hicks, Mr. Marr, Dr. Hinde, and Mr. Bauerman. In 

 thanking the Fellows for the reception they had given to his 

 jx-iper, Dr. Geikie said that a preliminary sketch of the results of 

 tlie receUwork of the Geological Survey in the northwest of 

 Scotland would, he hoped, be presented to the Society early 

 next year.— On the discovery of Trilobites in the Upper Green 

 (Cambrian) Slates of the Penrhyn Quarry, Bethesda, near Bangor, 



North Wales, by Dr. Henry Woodward, F.R.S. —On Theco- 

 spondylus daviesi, Seeley, with some remarks on the classifica- 

 tion of the Dinosauria, by Prof. H. G. Seeley, F.R.S. 



Entomological Society, December 7.— Dr. David Sharp, 

 President, in the chair.— Mr. Jenner-Weir exhibited, and made 

 remarks on, twelve specimens of Cicadetta heematoides, collected 

 last summer in the New Forest by Mr. C. Gulliver. — Mr. 

 McLachlan exhibited a %'p<t(i\m&xi olPterostiehus madidus, F., 

 which he had recently found in a potato. It seemed question- 

 able whether the beetle had been bred in the cavity or had 

 entered it for predaceous purposes. Mr. Theodore Wood, Mr. 

 Kirby, and Mr. Herbert Cox took part in the discussion.— Mr. 

 McLachlan also e.xhibited two specimens of a species of Tricho- 

 ptera — Neuronia clathrata, Kol. — which occurred rarely in Burnt 

 Wood, Staffordshire, and elsewhere in the Midlands. On in- 

 quiry he was informed that the two specimens exhibited had 

 been found in the Tottenham Marshes. — Mr. Porritt exhibited 

 a series of Cidaria russa'a, from Yorkshire, the Isle of Man, 

 the Hebrides, and the south of England. The specimens from 

 the two first- named localities were almost black. — Mr. Verrall 

 exhibited a specimen of Mycetcea hirta. Marsh., which was 

 found devouring a champagne-cork. The Rev. Canon Fowler 

 remarked that certain Cryptophagi had the same habit. The 

 discussion was continued by Mr. McLachlan, Mr. Jenner-Weir, 

 and Dr. Sharp. — Canon Fowler exhibited specimens of Acro- 

 nyeta alni and Leioeampa dietcea, which came to the electric 

 light on Lincoln Cathedral during the Jubilee illuminations. 

 He also exhibited a specimen of Harpalus melancholicus, Dej. 

 — Mr. Billups exhibited, for Mr. Bignell, an interesting collec- 

 tion of British oak-galls. He also exhibited the cocoon and 

 pupa case of a South American moth, from which he had bred 

 140 specimens of a species of Ichneumonidfe. — Mr. O. Janson 

 exhibited, for Mr. C. B. Mitford, a collection of Lepidoptera 

 from Sierra Leone. — Mr. White exhibited a curious structure 

 formed by white ants at Akyah. — Mr. Waterhouse exhibited a 

 series of diagrams of the win^s of insects, and read notes of 

 observations on the homologies of the veins — a subject to which 

 he had given especial attention for some time past. Mr. Cham- 

 pion, Mr. Verrall, Mr. McLachlan, Dr. Sharp, and Mr. Poulton 

 took part in the discussion which ensued. — Mr. G. T. Baker 

 contributed descriptions of new species of Lepidoptera from 

 Algiers. — Mr. Gervase F. Mathew communicated a paper en- 

 titled " Life-histories of Rhopalocera from the Australian 

 Region." The paper was accompanied by elaborate coloured 

 drawings of the perfect insects, their larvas and pupae. — Mr. 

 F. Merrifield read a report of progress in pedigree moth- 

 breeding, with observations on incidental points. Mr. Francis 

 Gallon alluded to the close attention Mr. Merrifield had given 

 to the subject, and complimented him on the neatness, ingenuity, 

 and skill with which his experiments had been conducted, and 

 on the results he had obtained therefrom. Mr. Poulton, Dr. 

 Sharp, Prof. Meldola, and others continued the discussion. 



Chemical Society, December i. — Mr. William Crookes, 

 F.R.S., President, in the chair. — The fjllowing papers were 

 read : — The alleged existence of a second nitroethane, by W. R. 

 Dunstan and T. S. Dymond. — An extension of Mendeleeff's 

 theory of solution to the discussion of the electrical conductivity 

 of aqueous solutions, by Holland Crompton. — Note on electro- 

 lytic conduction and on evidence of a change in the constitution 

 of water, by Henry E. Armstrong. — Bismuth iodide and bismuth 

 fluoride, by B. S. Gott and M. M. Pattison Muir. — The action 

 of hydrogen sulphide on arsenic acid, by B. Branner, Ph.D., 

 and F. Tomicek. — Note on the constitution of mairc^allol, by 

 C. S. S. Webster. 



PARIS. 



Academy of Sciences, December 12. — M. Janssen in the 

 chair. — On the law of errors of observation, by M. J. Bertrand. 

 Two propositions are affirmed : first, that, if a given magnitude 

 be repeatedly measured, and the measures grouped by twos in 

 haphazard order, by selecting in each group the greatest of the 

 two errors committed the relation of the mean of the squares 

 of these greatest errors to the mean of the squares of all the 



errors will converge towards the value i -f — , when the number 



of essays increases indefinitely ; second, if the measures be 

 similarly grouped in threes, the mean of the squares of the 



