HARDWICKE'S SCIENCE-GOSSIP. 



19 



The Probable Temperature of the Primor- 

 dial Ocean of our Globe. — At a recent meeting 

 of the Geological Society a paper on this subject 

 was read by Robert Mallet, F.R.S., in which he 

 stated that according to the latest hypotheses as to 

 the quantity of water on the globe, its pressure, if 

 evenly distributed, would be equal to a barometric 

 pressure of 204*74 atmospheres. Accordingly water, 

 when first it began to condense on the surface of the 

 globe would condense at a much higher temperature 

 than the present boiling-point, under ordinary cir- 

 cumstances. The first drops of water formed on the 

 cooling surface of the globe may not impossibly have 

 been at the temperature of molten iron. As the 

 water was precipitated, condensation of the remain- 

 ing vapour took place at a lower temperature. The 

 primordial atmosphere would be more oblate and 

 less penetrable by solar heat than the present, and 

 the difference of temperature between polar and 

 ■equatorial regions would be greater ; so that, in the 

 later geological times, ice may have formed in the 

 one, while the other was too hot for animal or 

 vegetable life. Thus, formerly the ocean would be 

 a more powerful disintegrant and solvent of rocks, 

 mineral changes would be more rapid, and meteoric 

 agencies would produce greater effects in a given 

 time. 



Diatoms in London Clay.— Mr. W. H. Shrub- 

 sole has announced his opinion that he has found 

 several distinct species of Antidiscus in the London 

 clay formation. 



The "Patches" in Granite.— Mr. J. A. 

 Phillips has read a very important paper before the 

 Geological Society on this subject, in which he 

 states that patches resembling fragments of other 

 rocks frequently occur in granite, sometimes angular, 

 sometimes rounded, sometimes with clearly defined 

 boundaries, sometimes melting away into the sur- 

 rounding mass, generally finer in grain than the 

 latter. After a sketch of the literature of the subject, 

 the author described the results of chemical and 

 microscopic investigations of these patches in the 

 granites of Cornwall, Shap Fell, Aberdeen, Peter- 

 head, Fort William and North-eastern Ireland. 

 There are two classes of inclusions : (1) the result of 

 the abnormal aggregation of the minerals constituting 

 the granite itself, containing generally more plagio- 

 clastic felspar, mica, or hornblende than it, with 

 some other distinctions : most probably concretions 

 formed contemporaneously with the solidification of 

 the mass ; (2) fragments of included schistose or slaty 

 rock, often not very highly altered, caught up from 

 the rock-masses through which the granite has forced 

 its way. 



The Geology of Natal, &c — A communica- 

 tion on this subject has just been made by the Rev. 

 H. Griffiths to the Geological Society of London, in 



which the writer states that shales and sandstones are 

 the prevalent rocks from the coast for about twenty- 

 four miles inland. Here is a protrusion of granite ; 

 beyond the sandstones come ferruginous shales, with 

 scattered boulders of trap on the surface. The 

 northern third of Natal is white sandstone, formed 

 into hills and ridges by denudation, with a long trap- 

 capped plateau near Ilelpmakaar. Coal-seams occur 

 in the sandstones. There are frequent vertical pipes 

 in these sandstones which, the author thinks, mark 

 the site of trunks of trees, round which the sand-beds 

 had accumulated. Rorke's House and Isandhlwana 

 are near the above plateau. Near the former is an 

 extinct mud volcano. A remarkable " vitreous shale " 

 is found near the Buffalo ; isolated pinnacles of it 

 occur at the spot where the few survivors of the fight 

 crossed that river. A range of mountains, with mural 

 escarpments, remnants of an ancient plateau, rising 

 to a height of some 2000 feet above another plateau 

 which is 5000 to 6000 feet above the sea, extends for 

 about 500 miles from the north of Natal to near 

 Cradock in the Cape Colony ; they are sandstone 

 horizontally stratified, capped by trap. Some other 

 geological features are described. The Transvaal 

 consists of undulating hills of soft limestone, a sand- 

 stone range, and a country rich in metals, — iron-ore, 

 cobalt, nickel, copper and gold occur, as well as 

 plumbago. 



A New Geological Section. — We strongly 

 recommend all our readers, geological science 

 teachers, &c, to procure Mr. J. B. Jordan's newly 

 issued " Geological Section," showing the super- 

 position and approximate maximum thickness of 

 sediment and strata in the British Islands." 

 (London : E. Stanford & Co.) It is the best of the 

 kind yet issued. 



The Geology of Leighton Buzzard.— We 

 have received a copy of some published lectures on 

 the above subject by Edward W. Lewis, F.R.G.S., 

 published by A. C. Muddiman (Leighton Buzzard). 

 In these lectures, which were delivered, we believe, 

 to working men, the lecturer has endeavoured, and 

 with much success, to convey the general truths with 

 as many local illustrations of them as come to his 

 hand. We congratulate Mr. Lewis on his success, 

 and heartily wish he had a representative in every 

 geologically representative district in Great Britain. 



Fossil Insects.— Few papers, among the many 

 which reach us, have impressed us with evidence of 

 harder or more zealous scientific work than those 

 which Mr. H. Goss, F.L.S., has contributed to the 

 Proceedings of the Geologists' Association. We 

 have just received part ii., on " The Insect Fauna of 

 the Secondary or Mesozoic Period." It is a most 

 exhaustive work, calculated to save a lifetime to the 

 man who follows Mr. Goss in this hard-worked field 



