Sept. 7, 1 882 J 



NATURE 



469 



crystalline axis of the Alpine chain, and in particular to the 



apparent identity of horizon occupied by the massive Schlern 

 dolomite, with its underlying St. Cassian Beds, and the Hallstatt 

 Limestone with its underlying marls rich in St. Cassian fossils. 

 This point is illustrated by sectional diagrams, one through the 

 Steiuernes Meer (after Mojsisovics), the other through the valley 

 in which St. Cassian is situated Numerous fossils recently 

 brought from the St. Cassian district were exhibited. 



On the Post-Miocene Depoits of Bovty Tracey, South Devon, by 

 W. Pengellv, F.R.S. — Lignites with detrital gravel are of Lower 

 Miocene or Upper Miocene age, and certain sub-tropical faults, 

 Betula nana beds of later date, of post-glacial age ; the so-called 

 "head" is of s imewhat older age, and is referred by some to 

 the glacial epoch. Described clay with angular smoothed 

 stones, considered to be Boulder Clay by Prof. I leer and otber 

 foreign geologists, but the author has failed to find any scratches 

 up m the stones. 9 foot 6 inches below the surface is a bed of 

 white clay with Betula nana. The author described the dis- 

 covery of a canoe in the midst of clays, which he believes of 

 older age than the era of Betula nana, and reports it to be 

 probably of inter-glacial age if the head » as of glacial age. 



Problems on the Geology of the Channel Islands, by Rev. E. 

 Hill, M.A., regards the work of the late Prof. Ansted as in- 

 complete. The author considers that probably the Homoblendic 

 rock overlie the grcups of sark, but this requires working out. 

 States that Prof. Ansted's conclusions as to the Jithology of the 

 rocks, are not founded on sufficient basis. He regards the work 

 of Prof. Liveing as of con-iderable value in this direction, but 

 he considers that there is much to be done in Guernsey, Sark, 

 and Jersey. He describes basaltic dyke?, dioretic dykes, and of 

 mica-trap in Guernsey, the latter being in Sark. 



The Southampton Artesian Well, by T. W. Shore and E. 

 Westlake. — The question is, whether it is possible by an exten- 

 sion of the existing well, to utilise it as a source of supply to the 

 town. The amount of water yielded by the well on the last 

 occasion of pumping, in 1851, was 130,000 gallons per day. 

 The quantity of water at present supplied to the town from the 

 Itchen is from 3 to 34 million gallons, but this is a much larger 

 quantity per head than is found to be sufficient for towns under 

 well regulated systems of supply. It thus appears that the well 

 yields about 1-25U1 part of the quantity required. For the pur- 

 pose of increasing the yield, two methods are suggested : one of 

 them is to drive galleries or drift-ways in the chalk, the other is 

 to continue the boring through the chalk into the Upper and 

 Lower Greens:mds. The work of excavation was carried on 

 from July, 1838 till 185 1, at a total cost of 19,000/., and reached 

 a total depth of 1317 feet. The diameter of the well was 13 feet, 

 d ininishing to 7 feet ; it passed through 464 feet of the Tertiary 

 Beds, of which soil occupied 2 feet, Lower Bag^hot bed 74 feet, 

 304 feet of London clay, the latter consisting of sandy clay with 

 seams of water-oearing sand and pebble beds towards the top ; 

 84 feet of Plastic Clay, with the usual bed of greensand on the 

 bottom. The chalk was reached at a depth of 464 feet, where 

 the masonry was terminated, but the 7-feet shaft was carried 99 

 feet into the chalk ; a 74 inch boring was then made with a 74- 

 inch augur to a further depth of 754 feet, making a total of 853 

 feet of chalk. The whole of the chalk contained flints, with the 

 exception of the last 10 feet. Most of the water met with 

 appears to have come from the chalk ; previous to the boring 

 being made, in 1S42, 20,000 gallons was raised. In 1844 the 

 quantity rose to 50,000 gallons, and finally in September, 1851, 

 to 130,000. The chalk thus supplies 5-6ths of the whole 

 quantity. The authors then give a description of the Brighton 

 chalk wells, and they consider the conditions are similar at 

 thampton. The authors, following the advice of Dr. 

 Buckland at the previous meeting of the British Association, 

 have ascertained the height of the Greensand springs : — 



c„ rin „. Height of Height of Water 



Spnngs ' Springs. in Well 



STwyford 2IO — 

 Petersfield 300 150 

 Ea<t Wordham ... 390 — 



Kingsclcre — 137 



I'ewsey I Avon at j 



Warminster ( WiveUford j " 34 ° I23 



Wiley at \ 

 Boreham Bridge / '" ^ 7 II2 



^{ N Bartd at | *» *7 



The authors are of opinion that large stores of water may be 

 obtained by sinking into the Greensands. 



W'ardour 



Shaftes' 



On the Synclinal Structure of the Straits of Dover, by W. Top- 

 ley, F.G.S. — Transverse valleys of the Weald, now dislocations or 

 anticlinal-, but, on the contrary, lie in synclinal flexures, this is 

 observable in all the valleys of the Weald. The author con- 

 siders there were six valleys on the north side of the Valley of 

 the Weald, five of which still exist. The sixth intersected the 

 Straits of Dover, its upper tributaries and the Mother, which 

 now enters the Channel at Rye. 



On Subsidence as the Effect of Accumulation, by Charles 

 Kicketts, M.D., F.G.S. — There is no fact in physical geolog y 

 more frequently recorded than that, whilst the deposition of 

 sedimentary strata has been in progress, there has been simul- 

 taneously a subsidence of the earth's crust ; though but little 

 effort has been made to determine whether they are dependent 

 on each other as cause and effect. Boring in deltas prove that 

 depression to a great extent has occurred whilst the accumulation 

 was being deposited. The greater amount of detritus derived 

 from hills and valleys is carried into the sea, but, instead of 

 filling it up, the water becomes of a great depth at a few miles 

 from the mouths of large rivers. There was a progressive 

 subsidence of the land during the glacial period ; this may be 

 ascribed to the weight of accumulated snow, and of the newly- 

 formed boulder-clay ; a similar depression is occurring in Green- 

 land, under a rapid increase of snow. The carboniferous series 

 above the limestone afford most satisfactory evidence that the 

 amount of subsidence coincides with that of deposition ; the 

 surface of the limestone and the beds of coal furnishing suffi- 

 ciently correct base-lines for determining the question. There 

 must needs be a cause for this universal occurrence of subsidence 

 with deposition of strata, the only efficient one being the weight 

 of the accumulated material pressing down the crust of the earth 

 resting upon a fluid substratum. Elevation also happens on the 

 removal of pressure, and " those regions which have suffered the 

 greate.-t amount of denudation have been elevated most." — 

 (Capt. Dutton, U.S. Ordnance Survey). At the termination of 

 the glacial period, the land, depressed by its load of snow, 

 became, upon this melting away, re-elevated to a certain extent. 

 This, and the rising of the land at the present time in Norway 

 and Spitzbergen, may be attributed to the removal of a thick 

 covering of snow. In elevated districts the highest parts are 

 those in which there has been the greatest amount of denudation, 

 and often consist of the lowest rocks in a geological series. The 

 author thinks that these depressions and elevations cannot be 

 ascribed to secular cooling of the mass of the earth, since by such 

 action the accumulation cannot also be Jaccounted for ; nor could 

 the same agency acting only in one direction cause both depres- 

 sion and upheaval. The concurrent pheomena of accumulation 

 and subsidence, and their converse, demand serious and careful 

 investigation ; especially as in them may be found the great 

 moving-power upon which depends the greater number of geo- 

 logical changes. 



On the Origin of the Hematite Deposits in the Carboniferous 

 Limestone, by Edward Wethered. — The author contended that 

 the so called "pockets" of haematite which occur in the Car- 

 boniferous Limestone were caverns and fissures into which the 

 ore had been introduced by water agency. There were two or 

 three signs which indicated an approach to a pocket of ore : — 



1. Joints appeared in the rock, through which water percolated. 



2. An ordinary cavern opened out, termed by the miners a 

 Welsh "locus," the sides of which were coated with large 

 crystals of carbonate of lime. 3. Traces of iron are found in 

 the "locus." The fact that the first indications of ore were 

 cracks in the rock, down which water percolated, certainly 

 pointed to the inference that by a similar percolation the 

 hamiatite has bean brought into its present position. That it 

 has been deposited by aqueous agency was clear from the crys- 

 talline character of some of the ore. Further, there was just what 

 would be expected from «ater containing the carbonates of line 

 and iron in solution when not exposed to the atmosphere, namely 

 lime has been first deposited, and subsequently hydrated peroxide 

 of iron. The next point considered was, from whence was the 

 iron derived. The highly ferruginous character of the Carboni- 

 ferous strata was well understood, and the fire- clays indicated 

 that large quantities of iron had been rendered soluble by the 

 deoxidising influence of decaying vegetable matter, and removed 

 by the percolation of water. But as to whether it was this iron 

 which had given rise to the Carboniferous Limestone hsematite 

 deposits was a matter for consideration. It was doubtful whether 

 there would have been sufficient time for the fissures and caverns 

 to have so far developed as to form receptacles for the Coal- 



