on the North Downs at altitudes of 500 feet to 600 feet as belonging to the Bagshot or later Eocene ; and these lie either on the Chalk or on the Reading Beds. This has been discussed by the author elsewhere.* If, as the hypothesis requires, some accentuation of the synclinal during the latter part of the London Clay period and during the Bagshot period, took place (against which no à priori reason can be alleged), the facts just enumerated would receive a rational explanation. The Upper Bagshot Sands, however, retain remains of a fauna, which indicates the conditions obtaining in a marine estuary; and as these have now been identified as far west as Highclere it would seem that towards the close of the Eocene period a narrow arm of the sea extended from the open sea towards the east, westwards as far as the place just mentioned, and perhaps somewhat further. This will be better understood by reference to the section (Fig. 1), which is, of course, like the next, only a diagrammatic representation, drawn through the longtitude of Windsor, of what was probably the relation of things in the Tamisian area towards the close of the Eocene period.

THE PLIOCENE PERIOD. (See Fig. 85.) In the shallowing of the waters of the Hants and Seine Basin during the Oligocene period, we seem to have the initiation of a more general upward movement, which perhaps continued through the Miocene; the failure to identify any deposits of the latter period in the London and Paris Basins going to show that the south-east of England (as well as the north of France) were for all that length of time dry land, the superficial strata therefore undergoing destruction by atmospheric agencies. The chalk especially must have suffered enormous waste through the removal of its carbonate of lime by carbonated atmospheric waters, leaving its flints (in some places largely mixed with the clay residue of the chalk) to accumulate upon the uplands, both on the north and south sides of the Tamisian valley. just as we see them at the present time accumulated upon the chalk downs above Ventnor.†

With the Pliocene movements the Weald probably attained its maximum elevation; though there are reasons for supposing that this elevation was not commensurate throughout the whole distance, but somewhat in excess towards the western part, which was lifted above the sea, while further east marine waters still encroached upon it to a much greater extent, depositing strata of which the well-known Lenham deposits are the remnants. This is further borne out by the fact that on the north side of the

"Geol. Mag." for September, 1890, pp. 403 et seq.

See the author in "Proc. Geol. Assoc.,' vol. viii., "On the Bagshot Beds of the London Basin, and their Associated Gravels;" also the " 'Journal of the Geol. Soc.," vol. xlvi., p. 558. See "Geol. Mag.," loc. cit.

Tamisian area there must have been towards the east some depression, with the consequent encroachment of the waters of the Anglo-Germanic Sea, laying down the Crag of the Eastern Counties, and filling up the valleys and hollows which had been cut into the London Clay during the preceding Miocene elevation of the area. The great Pliocene elevation of the Weald, which, working independently, both Professor Prestwich and the author have come to regard as the most important factor in determining the present surface-geology of the south-east of England, which also probably had its counterpart in a more regional elevation on the Mercian side, would seem to have two most important results: (1) it gave a general tilt to the north of the Eocene strata of the Tamisian area, and so threw the main line of drainage further north, initiating the present actual Thames Valley, while erosion was facilitated along that line by the weakness of the strata themselves; (2) a higher gathering-ground for tributary waters from the Wealden hill-range, and a general declivity to the north of the Eocene area, furnished the requisite conditions for the transport of the flints of the Chalk region, the flint pebbles washed out of the Eocene beds as their destruction on the north flank of the Weald advanced, and the Neocomian chert fragments, which, together with the flints and a few quartz pebbles, constitute the materials of the Plateau-gravels.* The erosion of the uplands of the Weald had evidently by this time, made such deep incisions into the strata, as to lay bare to the action of denuding agencies considerable portions of the Neocomian or Lower Greensand ; though this proceeded slowly enough for the transverse drainage to cut down its valleys through the Chalk escarpment, which even then must have begun to take shape.

The one incision of this kind across the strike of the chalk on the Mercian side of the Tamisian area, that of the Pangbourne and Goring gorge, was in all probability initiated too in Pliocene time, but the area of drainage concentrated upon this line was much smaller than at present. It would appear that the head-waters of the present Ouse are cut off from those of the Cherwell and the Thame by a watershed largely composed of glacial drift; at least the author's own observations of that district have led him to regard this as probable. If this were so, we should have to date the outlining of the present Upper or Oxford Basin of the Thames rather late in Quaternary time, the Pangbourne gorge having been no doubt deepened considerably during the Glacial period.

The tilting to the north of the Eocene strata, as a result of the great Pliocene elevation of the western portion of the Weald, perhaps affected the more

Journal of the Geol. Soc.," loc. cit.; also Prestwich, ibid., vol. xlvi., on the Southern Drift.

easterly portion of the area but slightly. If the great east-and-west fault, which has been traced along the Thames Valley below London,* can be dated back to Pliocene time, it probably had much to do with the definition of the main line of drainage towards the east. With this great Pliocene movement was also connected probably the minor differential movement, which lifted up the Chalk and Eocene strata along the Windsor-Marlow axis, turning the course of the ancient valley still further to the north between Reading and Windsor, and accounting for the elevation of the chalk which forms the site of Windsor Castle. The present angle which the river makes, as it turns northwards to Henley, has perhaps been the result of special and local erosion of the Eocene strata at a somewhat later period, owing to the great increase of the erosive power of the river, after the deepening of the Pangbourne gorge, and the inflow of the waters collected from the present Oxford Basin.

The case here supposed of the determination of a main line of drainage by a general tilting of the strata is not a solitary instance of the kind. It can te paralleled, on a much grander scale, by the general tilting (also to the north), of the great Tertiary series of strata deposited in the narrow Helvetico-Germanic sea, which skirted the Alpine chain before the period of its last and greatest elevatory movement. Across the gentle declivity

thus formed of Tertiary strata the drainage of a great part of the Alpine chain, including the whole of the Eastern Alps, now finds its way to join the Upper Danube, which, as von Dechen's Map of Germany shows, skirts the old Mesozoic country of Bavaria and Würtemberg, and the still older Archæan region of Upper Austria, all the way from its emergence from the Black Forest country down to Krems. This we must certainly connect with the last Alpine elevation.

(To be continued.)

SCIENCE-GOSSIP.

DR. W. SOMERVILLE has been appointed by the Techinal Education Committee of the Northumberland County Council to the Professorship of Agriculture and Forestry recently founded in the Durham College of Science, Newcastle.

We are sorry to announce the death of an old and frequent correspondent of SCIENCE-GOSSIP, Mr. Andrew Brotherston, of Kelso, at the age of fifty

seven.

BETWEEN December 9th last year and February 5th, seven great bustards (Otis tarda) were shot (of

• Whitaker, "Mem. Geol. Survey," vol. iv., p. 353.

course!) in Norfolk, Suffolk, Essex, Sussex, Hants, Wilts, and Carmarthenshire.

MR. S. W. BURNHAM, with the great Lick refractor (California), has observed the nearest companion of Aldebaran, while passing through its periastion at a distance of only o'13" from the large star. And from old measures of position, angle, and distance, he has obtained a satisfactory orbit.

MR. EDWARD BARTLETT (son of Mr. Bartlett of the "Zoo") has been appointed Curator of the Government Museum at Sarawak.

The following are the Lecture Arrangements of the Royal Institute after Easter :-Mr. J. Scott Keltie, Three Lectures on the Geography of Africa, with special reference to the Exploration, Commercial Political Development, and Partition of the Continent; Dr. E. E. Klein, Three Lectures on Bacteria their Nature and Functions (the Tyndal Lectures); Mr. William Archer, Four Lectures on Four Stages of Stage History (the Betterton, the Cibber, the Garrick, and the Kemble Periods); Professor Dewar, Six Lectures on Recent Spectroscopic Investigations; Dr. A. C. Mackenzie, Four Lectures on the Orchestra considered in connection with the Development of the Overture; Professor

Slyvanus P. Thompson, Four Lectures on the Dynamo; Mr. H. Graham Harris, Three- Lectures on the Artificial Production of Cold; Professor A. H. Church, Three Lectures on the Scientific Study of Decorative Colour. The Friday Evening Meetings were resumed on April 10th, when a Discourse was given by Sir William Thomson, on Electric and Magnetic Screening.

GOOD news for potato growers! Sulphate of copper has been found not only an antidote to potato disease, but also highly conducive to an improved and heavier crop, in some instances to the extra value of 57. an acre.

MR. C. VERNON BOYS has been making measurements of the heat of the moon by means of his very delicate 'radiomicrometer. His method was to focus the rays of the moon on the face of the radiomicrometer by a reflecting telescope of 16 inches aperture. In the case of a new moon, he found that the heat coming from its disc diminished as you passed from the convex to the concave edge, and that from the dark surface was so slight as not to affect the apparatus. The maximum radiation of heat came from points of the disc itself, not from its limbs. At full moon the maximum point was at the centre of the disc. The side of the moon which had been exposed to the sun for fourteen days was not warmer than that which had been exposed for seven days. No sensible heat was observed to come from the stars.

THE Eleventh Annual Exhibition of the S. London Entomological Society, was held at the Bridge House Hotel, London Bridge, S. E., on Wednesday, the 15th ult., and was continued on the Thursday following from I P.M.

MICROSCOPY.

PRESERVATION OF MELICERTA RINGENS.-Last May you inserted a paragraph bearing the above heading, in which I narrated how I had preserved in captivity this organism for twelve months without any interregnum. I have to-day to recount a further success in this matter. During the last year I have never been without numbers of this rotifer; at the present time I have very many. Only once have I feared that I might lose this attractive creature altogether, and this was on my return home last October, after my autumn holiday. I found during my absence that certain juvenile members of my family, out of the overflowing kindness of their hearts, had fed the sticklebat with pieces of biscuit as large as hazel nuts, and the plants, too, had been permitted to grow unpruned; consequently, on my return, I found the whole aquarium exceedingly offensive, necessitating a thorough cleansing. This was given, together with a reduction in the amount of plant-life, and the first change of water for over two years. The pruning of the weeds proved to be a somewhat dangerous experiment, plant growth at this season of the year naturally almost ceasing; this, together with the exceedingly severe winter, for a short time imperilled the maintenance of the whole. Fortunately all, however, has gone well, and melicerta has continued abundant; so numerous, indeed, as to become so crowded upon the somewhat scanty plants as to cause them to attach their tubes to one another in the manner we are informed more common in the American waters than our own. I have to add that I still consider the plants named in my previous communication to be very good plants for a small aquarium. The sticklebat still survives. Can any reader inform me as to the natural duration of life of this fish?-7. W. Measures, M.R.C.S.

ZOOLOGY.

MOUNTING SHELLS.-From a paragraph in the April number of SCIENCE-Gossir, I see that a correspondent has got into difficulties on the above subject. To my mind mounting good shells on tablets is downright sinful, as, no matter what mounting media are used, the specimens are certain to be more or less injured. Though I do not "mount" my own collection, I can speak with considerable experience as to its pernicious effect, as only too many of the specimens I receive in exchange are spoilt by one or

more unsightly patches showing where they have formerly been fixed to tablets. Judging from the instances I have seen, the various gelatine cements, especially those which are applied in a heated condition, are the worst offenders. At the Natural History Museum I believe they are very thick gum arabic, which is open to less objection, but perhaps the best cement, though possibly not a very secure one, would be wax (preferably such as is used for modelling) as it can be readily softened by moulding in the fingers. But why mount shells at all? a collection is far more useful when it is possible to take up each specimen separately and examine it on all sides without the necessity of first detaching it from a mount. Undoubtedly the best, though unfortunately rather expensive, method of storing shells is to keep them in glass-top boxes, rectangular being superior to circular ones. The most convenient dimensions are: depth three inches; width two and four inches; length, varying in half inch steps, from one inch upwards. The British Mollusca and part of the general collection at the Natural History Museum are arranged in this way. Card-board trays come next in order of merit, and as they can be easily and quickly made by an amateur after very little practice, are very cheap. The superficial dimensions given above for boxes will be found convenient for these also, but a depth of half an inch is sufficient. In order to save work, the corners need not be bound. In my own collection through want of funds, boxes. and trays are used together in the same drawer, the boxes being reserved for delicate specimens which might be broken if loose in a tray. As the boxes and trays are made on the same system they fit in exactly. While on this subject, I might refer to another method of spoiling shells, namely writing on the specimens themselves. Names and other information should always be written on a slip of paper placed in the box or tray, but I hope soon to speak about labels more at length.-S. Pace, 252 Fulham Road, S.W.

A NEW VARIETY OF HELIX CANTIANA.-The specimen to which the following description applies was taken from near Sittingbourne, in Kent, by Miss Muriel Norton, and forwarded to me for the purpose of naming by Mr. W. E. Swanton, who has it now in his collection. As far as I am aware, the variety is new-indeed, very few varieties of H. cantiana have been described-but, as its deviations from the type are distinctly marked, I have considered it worthy of a variety-name, and have called it var. canaliculata. The specimen resembles in some features what I have previously described as var. elevata in the first number of the "Conchologist" (readers of this note of mine on this variety will kindly oblige the writer by erasing the semicolon between the words "spire" and "compressed," and in reading "canaliculate" instead or 66 canaliculata,") but, in this instance, the spire is depressed and does not rise about half a

millimetre above the body-whorl. Var. canaliculata, Willms. Shell white, rather solid; suture between body-whorl and preceding whorl deeply and triangularly canaliculate; spire depressed and very slightly elevated above the upper level of the body-whorl ; umbilicus somewhat wider than in type and exposing more of the whorls within. Width fifteen mill. ; height nine mill. The most distinctive characteristics are the sub-depression of the spire, and the deep triangular canaliculation of the suture between the body-whorl and the spire.-7. W. Williams.

TWICE-USED NESTS.-In the April number of SCIENCE-GOSSIP, p. 93, Mr. H. G. Ward records an instance of a blackbird using the same nest for a second brood immediately after the first had flown. I had two similar instances lately in my garden. Both the blackbird and the thrush used the same nest in the same season for successive broods. The thrush was successful in rearing both broods, but the blackbird was unfortunately interfered with by a cat. I mentioned the circumstance at the time to Mr. Seebohm, who said it was very unusual.-J. Jenner Weir, Beckenham.

ROSSENDALE RHIZOPODS.-In the last paper on this subject, Fig. 59, 60, 61, should be Amaba proteus. The names of Figs. 63 and 66 should be transposed.

DEEP SEA EXPLORATION IN THE EASTERN MEDITERRANEAN.-The investigations which the expedition sent out by the Vienna Academy of Sciences has been carrying out in the eastern portion of the Mediterranean have been very successful. The investigations concerning the depth and general characteristics of the sea, and the presence of life in it, were carried out at seventy-two distinct points. The greatest depth (3700 metres, or over 2 miles), was found near the great depression which runs between Molla and Cerigo-a deep valley running in a direction from north to south, and with a depth varying from 3500 to 4000 metres, the descent being much more abrupt on the Greek side than on the Italian and Sicilian side. Experiments as to light showed that the waters are more transparent near the African coast than in the northern portions. There white metal plates were discernible at a depth of nearly 144 feet. Sensitive plates were still found capable of being acted upon by a light at a depth of nearly 550 yards (24 furlongs), at a point 200 marine miles north of Ben-Ghazi; on being drawn up they were found to have been blackened. The acid constituents of the sea-water seem to be the same at the greatest depth as near the surface, nor is any difference in the quantity of ammoniacal constituents perceptible between the upper and the lowest levels, with the exception that everywhere close to the bottom the quantity of ammoniacal ingredients is notable. The deep-sea region of the

Eastern Mediterranean is very poor in animal life. A dredge at a depth of 3000 metres brought up no animal specimens at all, but at a depth of 2000 metres leaf-formed algæ were discovered similar to those found at the same depth in the Atlantic by the Panton expedition.

ORNITHOLOLOGICAL NOTES FROM Chichester.The excessive severity of the past winter, prolonged almost without intermission, save for a brief respite of beautiful weather in February, from the close of November to the beginning of April, caused a terrible destruction of bird life. Perhaps none have suffered worse than those sweet songsters the thrushes (Turdus musicus), numbers of which, with their relatives the redwings (Turdus iliacus), and fieldfares (Turdus pilaris), died either from cold or starvation. Swarms of wildfowl visited our shores, and received, alas! poor things, in many cases anything but a hospitable reception; for, rightly or wrongly, according to our particular standpoint, I suppose though as a member of the Selborne Society I must enter my protest-the sportsman embraced what to him was, as all cold winters are, a golden opportunity for sport. Amongst other common birds the following were seen, and some of them shot in the neighbourhood of Chichester in the months of December and January: Wild Swans Hooper (Cygnus musicus). Of these a flock of thirty-one was seen off Selsey. Geese : The common Brent-goose (Bernicla Brenta) has abounded. Specimens of the bean goose (Anser segetum), and of the white-fronted goose (Anser albifrons), have also occurred. Ducks: Twentyeight Sheldrakes (Tadorma cornuta) were observed together in Chichester Harbour, as well as a number of tufted ducks (Fuligula cristata), and scaup ducks (Fuligula marila). Smews: Two smews (Mergus albellus) were taken at Fishbourne, and two or three goosanders (Mergus merganser). Bitterns: Two bitterns.-One at Fishbourne, and one at Earnley. The above communication from a capital sportsman-naturalist will prove interesting to many of your readers.-Joseph Anderson, jun., Hon. Curator, Chichester Museum.

BOTANY.

VARIATIONS OF COLOURS IN PLANTS.-In the Black Mountains on the borders of Monmouth, Brecon, and Herefordshire, the harebell, and many other species of bell flowers, grow very profusely. Some years ago I found a few white harebells in the Grwyne Fechan Valley. As botanical friends rather doubted this, during the season of 1890, I paid some attention to the variations in colour of these flowers. All through the Black Mountain country the harebell varies from a reddish purple to a very pale shade of blue, and white specimens are not infrequently met

now.

with. Generally, the white harebells look like washed-out blue ones, with a very faint tinge of blue and a somewhat sickly appearance. I have, however, very rarely found a strong growing plant with opaque, creamy white flower, notably last August one plant on the N.E. slope of Mynydd Pen y fal, near Abergavenny. These really white harebells almost seem like a distinct variety. Is not the white harebell commoner in France than in England? Anne Pratt mentions it, giving the popular name, I think, as "la religieuse des champs;" but I unfortunately have not her "British Flowering Plants" by me In addition to the plants named by your correspondent, Mr. H. G. Ward, we found last year in a lane between Abergavenny and Crickhowell the common scabious (Knautia arvensis) with perfectly white flowers. In the parish of Henllis, near Newport, columbines occur in purple, blue, rose pink and white. The bugle is occasionally found white, and the common wood sorrel is occasionally red. Around Newport the common purple orchis (O. Morio), where it grows in abundance, is always found in four colours, viz. : purple, coral pink, light coffee colour, or écru and white, the lighter colours being the least frequent and the green lines in the hood being a striking feature in them. In the; Quantock country, in Somersetshire, the bee orchis is found with three white petals.-Thomas Jones, Newport, Mon.

THE POST OFFICE AND BOTANISTS.-Would any brother botanists, who have exchanges with foreign countries, join me in trying to obtain the same privileges from the Post Office, as our foreign confrères have? They are able to send their plants here as "business papers "by the printed matter post, costing them about 4d. per lb., whereas we have to pay Parcel Post rate even for a few ounces, or else letter post rate at 24d. per § oz. The lowest rate for foreign Parcel Post is about Is. 2d., and to the United States, Letter Post is the only one we can send plants by, there being no Parcel Post. From the States parcels of plants can be sent here at 4d. per lb., and the packets may weigh up to 4lb. To make a return exchange, for these we have to pay through the Parcel Express Companies at about Is. and upwards per lb. Could not a petition to the PostmasterGeneral be got up about this? I believe that among the United States postal regulations, there is a special one regarding the postage of dried plants.-A. E. Lomax, 56 Vauxhall Road, Liverpool.

FLORA OF KENT.-With reference to paragraph on this subject in April number, p. 90, there is no complete Flora of the county; but Cowell's "Floral Guide to E. Kent," "Wild Flowers of Dover and Neighbourhood," and Jenner's "Flora of Tunbridge Wells," may be consulted with advantage. Also G. Smith's collection of rare plants from S. Kent, D. Cooper's "Flora Metropolitana," Irvine's "London Flora," and E. de Crespigny's "New

London Flora for W. Kent," besides the Report of the Greenwich Natural History Society of the District between the Rivers Cray, Ravensbourne, and Thames. Milne and Gordon, N.E., and S. Kent, 1792; and T. Johnston's "Iter," N. Kent. N. and S. Kent, 1629 and 1632, would be too antiquated to be at all useful; as also would be Petiver's "Journey from London to Dover," and Blackstone's Species;" but there are many records of later date to be found in the pages of the "Phytologist," from 1855 to 1862; in those of SCIENCE-GOSSIP Exchange and Locality Record Clubs' Reports and other periodicals; not to mention Watson's "New Botanist's Guide." Dr. de Crespigny's Handbook may be procured at Messrs. Allen & Co.'s, Limited, Waterloo Place. A new edition is ready for the press, revised, rearranged, and with much additional matter, itinerary and chart 35 to 40 miles round.Ede.

CUTICLES OF LEAVES.-What is the best way of getting the cuticles of geranium and leaves such as abutilon, and Cheiranthus incana so as to mount them as transparent objects? Jabez Hogg, in his work on the Microscope, recommends, p. 440, "immersing the leaf in sulphuric ether," but as his book was written in 1856 I thought some fresh way might have been found out since that time.-G. A. Hankey.

A VARIETY of the male fern (Lastrea pseudo-mas) has been found by Mr. Wilson, of Alford, N.B., which is new to botanists. Fronds have been also examined by Mr. Wollaston, of Chislehurst, who calls it Lastrea pseudo-mas, var. multiformis, Wilson (Wol.). The nearest previously-known form to this was found by the late Mr. Barnes, of Levens, in Lancashire.

GEOLOGY, &c.

ON PHOSPHATIC CHALK AT TAPLOW.-The following highly important paper was read at the last meeting of the Geological Society, by Mr. Strahan. Two beds of brown chalk in an old pit near Taplow Court owe their colour to a multitude of brown grains. These grains are almost entirely of organic origin, foraminifera and shell-prisms forming the bulk of them. Mr. Player has analysed specimens of the brown chalk, and finds that it contains from 16 to 35 per cent. of phosphate of lime. The tests as well as the contents of the foraminifera to have been phosphatized, the phosphate appearing as a translucent film in the former case, In the case of and as an opaque mass in the latter. the prisms of molluscan shells, the whole of the phosphate appears to be in the opaque form. Minute coprolites also occur, together with many small chips of fish-bone, in which Dr. Hinde has recognized lacunæ, while some have been identified

seem