SCIENCE-GOSSIP. 



25 



enormous thicUness, stretching along for miles and 

 miles on the sides of the Huniber, can appreciate their 

 magnitude, and speak as tu the inadequacy of the 

 three rivers flowing into the esluar)' to lay down such 

 extensive deposits. It would be interesting if similar 

 experiments to those made at Vorlv could be conducted 

 nearer Goole, though allowance would have to be 

 made for material brought in by the rise of the tide. 

 Of course Mr. I'latnauer's note was not written for the 

 purposeof showing what amount of material eventually 

 reached the Humber in the form of sand and mud. He 

 simply demonstrates in a very lucid manner what 

 geological work is actually being performed by the 

 river Ouse. If similar observations could be system- 

 atically undertaken on our other rivers, some very 

 valuable results might be obtained. We anxiously 

 await the appearance of Mr. I'latnauer's further notes. 

 — Tlioiiias SJicppard, y8, Shcrhurn Street, Hull; 

 iSlh April. 



Brighton Cliff Formation.' — Referring to Mr. 

 E. A. Martin's note on the fine section of the chalk 

 breccia or Coombe Rock displayed in the cliffs to 

 the east of Brighton (S.G., Vol. v., N.S., p. 376), it 

 may interest the readers of Science Gossip to know 

 that to the west of the town there is a good expo- 

 sure of the bed of sand, which, owing to the inroads 

 of the sea, has, as Mr. Martin remarks, since dis- 

 appeared from the eastern side, where it occupied a 

 position nn'dway between the Chalk and the raised 

 beach. This occurs in a small quarry on the sea front 

 at Portslade, where is seen the Coombe Rock, much 

 reduced in thickness, resting on a bed of marine sand, 

 exposed to a depth of six feet. At the eastern part 

 of the cutting there are a few rolled flints in the 

 top part of the sand. They are the sole representa- 

 tives of the mass of shingle under and on the other 

 side of Brighton. I have obtained specimens of 

 Mytilns cdtilis from the ancient beach. This 

 mollusc, together with Littorina obtusata, is very 

 abundant in the sand, and pebbles encrusted with a 

 species of Baianus are not uncommon. Both 

 have yielded remains of a whale, Balaena 

 iiiystieeta. Many mammalian bones, including 

 teeth of Elephas priiiiigenius and Rhinoceros 

 antiqtUtatis, have been exhumed from the Coombe 

 Rock. Specimens of all these, together with a 

 Palaaolithic flint implement from the base of the last- 

 mentioned formation at Portslade, can be seen in the 

 Brighton museum. The Coombe Rock covers up all 

 the marine drift of the Hampshire Basin, where it 

 can be traced to the dry chalk valleys of the South 

 Downs and their westerly extension, from each of 

 which it projects on to the lower ground in the form 

 of a large semi-circular talus. The origin of this 

 curious deposit is not fully known, but it seems to 

 have been formed during a period when extreme cold 

 was the predominant feature. It is not difficult to 

 imagine that severe frosts had strewn the chalk 

 slopes with a deep layer of rubble. In the winter, 

 wind storms would seal this up under a cover of 

 snow, which would be congealed into a neve. Under 

 the influence of the summer heat, this minor ice- 

 sheet would partially melt, and great masses would 

 slide down the hillsides, dragging with them the loose 

 debris, and the boulders of sandstone which were 

 already scattered over the downs. On the final dis- 

 integration of the ice and snow, piled up by this 

 process in the bottom of the valley, great floods 

 resulted, which swept much of the detritus far out into 

 the plain below. Mr. C. Reid speaks of the mass 

 covering Selsey Bill, as being coarse and gravelly to 

 the north, and loamy to the south. This is just what 

 one might expect, for the process of sifting the larger 

 from the finer material, and the carriage of the latter 



further afield, would be going on long after the 

 torrential waters had spent their original energy. — 

 J. P. Johnson, cjo Stanley and Co., High Street, 

 Sutton, Surrey. 



Glacial Drift of Wheathampstead. — At Mill 

 Hill some gravel has been laid down as road-material, 

 which is full of fossils from the Chalk. There are a 

 great many sponges in it, chiefly Vcntricitlite and 

 Cliona, also Micraster and Salenia. Drift with 

 derived rocks and fossils, such as Cryphaea dilatata 

 and Belemnites from the Oxford Clay has also been 

 utilised, together with masses of freestone with 

 Rhynchonella angulata from the Inferior Solite. On 

 asking a man one day where these gravels came from, 

 he said they were brought from Wheathampstead. 

 I went down and visited the beds. There was plenty 

 of drift, but the sponges were not so abundant. Why 

 should the sponges be so abundant in the gravel, 

 wheieas in the south east of London the echinoids are 

 the most plentifid ? — G. Fletcher Brown, ^, Topsfield 

 Parade, Crouch End, N. 



Correlation of the Echinodermata. — In his 

 paper before the Geological Society on " Fossils 

 in the University Museum, Oxford : Silurian 

 Echinoidea and Ophiuroidea," Professor W. J. 

 Sollas called attention to the correlation of structure 

 and function in the locomotive organs of Asterids, 

 Ophiurids and Echinids. In the case of the two 

 latter, movement depends on tension directed along 

 the tube-feet. In Starfish this tension is met by the 

 disposition of the ambulacral ossicles in the form of 

 an arch ; in Urchins by a continuous tesselation of the 

 surface, which would only be weakened by arch-like 

 interruptions. If, however, urchins have evolved 

 from an Asterid stem, they may have originally 

 possessed arch-like ambulacral grooves, and the 

 present plates of the ambulacra may have been 

 subsequently acquired. In Palaeodiscus ferox of 

 the Lower Ludlow, Leintwardine, which by the 

 structure of the buccal armature is definitely shown to 

 have been an Echinid, the ambulacra possess just the 

 characters as theory anticipates ; an inner arch of 

 poriferous ambulacral plates, homologous with those 

 of a starfish, is closed externally by a series of paired 

 plates, which represent the ambulacral series of an 

 urchin. 



Growth of Stal.\ctites. — At a recent meeting 

 of the Royal Society of New South Wales, Professor 

 Liversidge exhibited some specimens of stalactites and 

 stalagmites from the tunnel at the Prospect Reservoir, 

 Sydney, which had been collected by Mr. E. Hufton. 

 The tunnel was built some twelve years ago, and the 

 comparatively large size of the stalagmitic deposit — 

 nearly 2in. in thickness — gives an idea of the rate 

 of deposition of calcium carbonate. The exhibitoi 

 believes they have been derived mainly from the 

 cement of the tunnel, inasmuch as he understands 

 that no limestone was used in its construction, nor is 

 there any in or about the reservoir. The catchment 

 area is essentially of sandstone, and the water conse- 

 quently poor in lime. 



Geology of Davos. — At the meeting of May 

 loth, of the Geological Society, Mr. A. Vaughan 

 Jennings, F.L.S. , F.G.S., read a paper on the 

 physical structure of the Davos Valley, which is 

 rather oblique to that of the great rock masses, but is, 

 however, somewhat irregular. These which have a 

 general dip towards the south and east, form three 

 great acute and rudely parallel overfolds ; the western- 

 most being the more complicated, and is partly 

 serpentine, with certain ciysalline Breccias, in the 

 vicinitv. 



