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GEOLOGY 1 ^ 



Iguaxodox at Kensington. — The Geological 

 Magazine for Julv, contains an illustrated article 

 by Dr. H. Woodward, F.R.S., President of the 

 Geological Society, upon the reconstruction of 

 Jguanodon in the British Museum, Kensington, 

 which is indebted to the assistance of Mans. E. 

 Dupont, the Director of the Royal Museum in 

 Brussels, for obtaining a coloured reproduction of 

 the entire skeleton of /. bernissartensis. This is now 

 on view in the reptile gallery of the geological 

 department. The article is of value to students of 

 geology on account of Dr. Woodward's description 

 of the find, in 1878, of no fewer than twenty-three 

 of these skeletons in Wealden strata, near the 

 village of Bernissart, between Mons and Tournay, 

 on the French frontier of Belgium. A trial gallery 

 made in order to discover the continuation of a 

 missing seam of coal, led to discovering an 

 ancient river-gorge, excavated by a stream in the 

 Jurassic period, through several hundreds of feet 

 of coal-measures, but long since filled up and 

 lost. This river-gorge is very rich in fossils, 

 and well stocked with fishes, reptiles, tree-ferns 

 and semi-tropical animals and plants. 



Aturia Ziczac in* Suffolk. — I beg to send you 

 a sketch and also a photograph of a magnificent 

 specimen of an extinct species of the Pearl}- Nautilus 

 which I recently found in the London clay cliffs at 

 Walton-on-the-Naze. The fossil weighs nine and 

 a half pounds, its lateral measurement, eight 

 inches, length on the dorsal curvature, nineteen 

 and a half inches, whilst the periphery or head 

 aperture measures five and a half inches in 

 diameter. The outer shell, although decalcified, 

 shows distinctly all the successive growths of the 

 laminae, and where the shell has been worn away, 

 the nacre or inner pearly coating is brought in 

 view, retaining in parts almost its original colour. 

 In places where the fossil has been denuded of 

 both shell and nacre, the septa or casts of the 

 nautiloid chambers are beautifully marked, and 

 still coloured as vividly as in life, although an 

 abyss in time has elapsed since the creature ceased 

 to exist. Dr. J. E. Taylor has declared this fossil 

 to be a perfect specimen of the elegantly propor- 

 tioned Nautilus, Aturia ziczac, a cephalopod 

 characteristic of the eocene formation, a stratum 

 immediately succeeding the chalk, and at an epoch 

 when the climate of this country was tropical. 

 Another interesting specimen of the London clay 

 had interstratified, to all appearance, two well- 

 defined miniature coal seams. These, however, 

 upon examination, proved to be highly carbonized 

 vegetation. The clay in that neighbourhood is 

 intermixed with crystals of selenite or sulphate of 

 lime, ranging from microscopic size to seven inches 

 in length, these latter may be split into very thin 

 plates and used in various polarising appliances. So 

 geologically rich are the cliffs at Walton, that on 

 the same visit, I made quite a collection of crag 

 shells, including the reversed whelk, the whole 

 being now on view at Wolsey House, Ipswich.— 

 A. Martinelli, 77, Hervey Street, Ipswich ; June, 1895. 



Notes & 



~X.u/' '11, '« 

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Fungoid Potato Disease. — Several potato 

 plants in my garden and in those of my neighbours 

 have this hot season suffered from a disease that 

 does not appear to be noted in any of the books to 

 which I have access. A few dark-brown irregular 

 spots appeared on the leaves about the end of May 

 or beginning of June. The leaves gradually turned 

 brown and very dry ; dark shiny spots appeared on 

 these dry leaves, something like those of Rhytisma 

 acerinum, but smaller. The infection spreads down 

 the stem gradually, and the whole of the stem 

 becomes dry and withered as if shrivelled by frost. 

 It is noticeable that separate leaflets may be infected 

 for a long time before the others. The old tuber 

 appears to be filled with a tangled mass of septate 

 mycelium, and I have found what appear to be 

 zoospores — small oval bodies in movement — and 

 talentospores — two or three thick-walled cells 

 coloured a dirt}" green. Later on, perhaps in 

 consequence of the drought, the dark patches did 

 not appear. The infection appears to travel down 

 the intercellular spaces, but in some cases cells 

 seem to be filled with very small black spores. Can 

 any of your readers tell me what fungus this is ? — 

 J.Lewton Brain, Swanton Motley, E. Dereham; July, 

 iS95- 



Chalk Rock ix Herts. — In a well recently dug 

 at St. George's School, Harpenden, Herts, this bed 

 was pierced at a depth of about no feet below the 

 surface, the height of which above sea-level is 

 410 feet. It had a thickness of three feet, and was 

 of a very tough consistency, markedly different 

 from the soft beds of upper chalk hitherto ex- 

 cavated. It seemed to consist at this spot, to a 

 very large extent, of the remains of echinoidea. 

 Owing to the hardness of the stone these were 

 generally broken across, showing a chalky interior 

 surrounded by a thin calcite shell with gleaming 

 cleavage surfaces. There were also present irregular 

 shaped nodules of a hard cream-coloured rock with 

 a dull green powder}' exterior. Some microscopic 

 sections which I prepared showed the substance of 

 the rock almost entirely composed of organic 

 remains — foraminifera, sponge spicules, spines and 

 plates of echinoidea — with very little amorphous 

 mud. Among the larger fossils were terebratulae 

 and rhynchonellae, beautifully preserved, small 

 ventriculites and casts of Pleurotomaria and other 

 gasteropods, with a few fish-teeth. Accessory 

 minerals were glauconite (very abundant — some 

 grains very large), flakes of mica, and many 

 rounded nodules of decomposed iron pyrites, 

 enclosed always in an ochreous covering. It is 

 interesting to note the position of the bed here, 

 compared with the long exposure in the cutting on 

 the Midland Railway south of Luton, four miles to 

 the north, at an altitude of 420 feet, and with that 

 at the summit of Kensworth Downs, above 

 Dunstable, nine miles away to the north-west at 

 800 feet. I have never seen any description of the 

 bed in the records of the well- sections below 

 London. — .V. E. Mclntire, Si. George's School, 

 Harpenden ; May 20th, 1895. 



