2S6 



NA TURE 



[July 19, 1894 



only 20 miles east of Ely, no Jurassic rocks exist, and the 

 Lower Cretaceous series is only about 32 feet thick, the beds 

 differing greatly from those of Cambridgeshire, but resembling 

 those of the same age in the Richmond boring. The Winkfield 

 boring (3J miles west-south-west of Windsor! was remarkable 

 for having been successful in obtaining water from the Lower 

 Greensand, and for the great depth (1243 feet) to which it was 

 carried for this purpose, the Gault being unusually thick. The 

 boring at Ware was for the first lime described in detail, and 

 former accounts were corrected from specimens preserved by 

 the New River Company. By this means, and with the as- 

 sistance of Mr. W. Hill, the authors were able to give a fairly 

 complete account of the rocks, and to determine the limits of 

 the divisions of the Upper Cretaceous series. They denied the 

 existence of Lower Greensand at this locality. Of the boring 

 at Cheshunt a complete account was given, based on information 

 and specimens supplied by Mr. J. Francis, the engineer of the 

 New River Company. The paper concluded with a tabular 

 view of all the borings in the East of England, showing the 

 level below ordnance datum .it which the Pala;ozoic floor occurs 

 in each. The President, Piof. Boyd Dawkins, Prof. Judd, and 

 Mr. Topley spoke upon the subject of the paper, and Mr. 

 Whitaker briefly replied. — The Bargaie Beds of Surrey and 

 their microscopic contents, by Frederick Chapman. This was 

 an attempt to correlate the Bargate Beds of Guildford 

 and its vicinity with the members of the Lower Green- 

 sand as known elsewhere in the south-east of Eng- 

 land. Mr. T. Leighton, Prof. Judd, Mr. Whitaker, Dr. 

 G. J. Hinde, Mr. Topley, and Prof. T. Rupert Jones offered 

 some remarks upon the paper. — On deposits from snowdrifts, 

 with special reference to the origin of the loess and the pre- 

 servation of mammoth-remains, by Charles Davison. When 

 the temperature is several degrees below freezing-point, snow 

 recently fallen is fine and powdery, and is easily drifted by the 

 wind. If a fall of snow has been preceded by dry frosty 

 weather, the interstitial ice in the frozen ground is evaporated, 

 and the dust so foimed may be drifted with the snow and 

 deposited in the same places. The snowdrifts as a rule are 

 soon hardened by the action of the sun or wind, and the dust is 

 thus imprisoned in the snow. As the snow decays, by melting 

 and evaporation, a coating of dust is extruded on the surface of 

 the drifts, and, increasing continually in thickness as the snow 

 wastes away, is finally left upon the ground as a layer of mud, 

 which coalesces with that of previous years. The deposit so 

 formed is fine in texture, unstratified, and, as experiments show, 

 mica-flakes included in it are inclined at all angles to the 

 horizon. The author described several such deposits both in 

 this country and in the Arctic regions ; and suggested (1) that 

 the loess is such a deposit from snowdrifts, chiefly formed when 

 the climate was much colder, but still very slowly growing ; (2) 

 that mammoths suffocated in snowdrifts are subsequently em- 

 bedded, and their remains preserved in the deposits Irom them ; 

 and (3) that the ground-ice formation of Alaska, &c., is the 

 remains of heavy snowdrifts when the coating of earth attained 

 a thickness greater than that which the summer heat can 

 effectually penetrate. Mr. Davison's theory did not find much 

 support. During the discussion upon it, Mr. Oldham said that 

 be happened to have a personal acquaintance with the deposits 

 left after the melting of snow and with the loess. The former 

 were found in sheltered spots on the ridges of the Himalayas, 

 which are annually covered with snow, but (so far as his ex- 

 perience went) they were denser and more compact than the 

 true loess ; they were, in fact, dried muds, while the true loess 

 was a dust. In the hills of the western frontier of India, where 

 loess was largely developed and still in course of formation, the 

 distribution, surface-contour, and constitution showed it to be a 

 wind-blown dust deposit, though it passed into deposits which 

 had been rearranged by water. Part of this lay at altitudes 

 where snow fell each year, but it was equally well and typically 

 developed bcfiw the level at which snow usu.illy fell, and where 

 It was not preceded by a long frost nor lasted long enough to 

 form extensive drifis. lie did not think that the true loess 

 could originate from the solid matter left by melting snow, and 

 i( could certainly be formed without the aiil of snow. Prof. 

 Blake, Prof. Boyd Dawkins, and Dr. W. F. Hume also spoke. 

 —Additions to the fauna of the 0/<rH<//«j/-zone of the north- 

 west Highlands I'X U- N. Peach, F'.R..S. New material 

 obtained by the officers of the Geological .Survey having been 

 placed in the author's hands, he was enabled to add information 

 concerning the ipecics of OttntUm previously described by him 



NO. 1290, VOL. 50] 



(O. Lapworthi) ; he also described a new variety of this species, 

 three new species of the genus, a new subgenus of Oleiitlltu, 

 and a form provisionally referred to Bathyiiotiis. He discussed 

 certain theoretical points based upon the study of the remains 

 described in the paper, and stated that these make it probable 

 that the dispersal of the Olenellids was from the Old World 

 towards the New. Dr. Hicks and Dr. G. J. Hinde spoke upon 

 the subject. — Questions relating to the formation of coal-seams, 

 including a new theory of them : suggested by field and other 

 observations made during the past decade on both sides of the 

 -Atlantic, by W. S. Gresley. \ number of new facts were 

 described, and the bearing of these and of previously recorded 

 facts upon the origin of coal was discussed, special reference 

 being made to the Pittsburgh coal. He maintained that the 

 evidence pointed to the formation of coal on the floor of an 

 expanse of water, by vegetable matter sinking down from float- 

 ing " islands " of vegetation, which may have been of very large 

 size, and enumerated cases of'such "islands" or "rafts" of 

 vegetation which have been described as existing in modern 

 times. — Observations regarding the occurrence of anthiacite 

 generally with a new theory as to its origin, by the same .author. 

 -Vfter discussing Dr. J. J. Stevenson's theory of the origin of 

 anthracite, the author described the nature and mode of occur- 

 rence of the anthracites of Pennsylvania, and gave his reasons 

 for concluding that the de-bituminisation of coal was not pro- 

 duced by dynamic metamorphism during mountain-building, but 

 rather by previously-applied hydrothermal action. He further 

 discussed the applicability of his theory to other cases of an- 

 thracite,' including that of South Wales and Ireland. In the 

 discussion that followed, Prof. Boyd Dawkins pointed out that 

 the anthracite-fields of South Wales and of Ireland are exactly 

 in those places where the coal-seams have suflered most from 

 crushing and faulting, and that therefore there is distinctly a 

 connection between the exertion of dynamical force and the 

 anthracitic condition. This also applies to the Irish fields. In 

 some cases a coal-seam can be traced into an anthracite seam. 

 In his opinion the author's views would not explain the presence 

 of anthracite in this country. — The igneous rocks of the 

 neighbourhood of Builth, by Henry Woods. — On the relations 

 of some of the older fragmental rocks in north-west Caernarvon- 

 shire, by Prof. T. G. Bonney, F. R.S., and Miss Catherine A. 

 Raisin. In a recent paper on the felsites and conglomerates 

 between Bethesda and Llanllyfni, North Wales, it was argued 

 that, in the well-known sections on either side of Llyn Pad.irn, 

 a great unconformity separates the rocks into two totally distinct 

 groups. The authors of the present communication discussed 

 at the outset the great physical difficulties involved in this 

 hypothesis ; a subject which, in their opinion, was passed ovr- 

 too lightly by the author of that paper. They further alTiruii 

 in the course of a description of the sections, which are ni 

 clear and afford the best evidence : — (l) That the strike in li 

 the supposed rock-groups is generally similar. (2) That il 

 same is true of the dips. (3) That very marked identity 

 lithological characters may be found in rocks on either side 

 the alleged unconformity, specimens occasionally being practi- 

 cally indislinguish.able. (4) That in no case, which has been 

 examined, can any valid evidence be found in favour "f 

 the alleged unconformity, and that in the one, which i^ 

 supposed to to the most satisfactory proof of it, the facts art 

 wholly opposed to this notion. Prof. Blake, Dr. Hicks, 

 and Mr. Whitaker discussed these views, and Prof. Bonney 

 replied. 



Royal Microscopical Society, June 20. — Mr. A. W. Ben- 

 nett in the ch.iir — Dr. J. E. Talmage described his method l"i 

 mounting and staining the brine shrimp, Arlania fcrlilis. — \h 

 W. H. Dallinger called attention to a stereoscopic photiimicro- 

 graph of injected muscle which h,-id been presented by Dr. W. 

 C. Borden. — Dr. Dallinger exhibited and described a new form 

 of mechanical stage for the microscope, which had been produced 

 by Messrs. Swift. Further remarks were made by the chairman 

 Messrs. Comber, Swift, More, and Beck. — Mr. J. II. Ilarviy 

 described a method of mounting opaque objects so that thi-y 

 could be moved in all directions whilst under examination. - 

 Mr. T. Comber read a pa|)er on the unreliability of cert.iin 

 characters generally accepted for specific diagnosis in the Dial" 

 maceic. A discussion ensued, in which the chairman, I'lof 1 

 J. Bell, and Mr. J. Badcock took part. — Prof. Bell gave . 

 ti'suwJ u{ Mr. F. Chapman's sixth paper on the Foraminifera ol 

 the Gault of Folkestone. 



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