Meyer led the party to a quarry of the Lower Greensand west of Guildford, where the upper member of this interesting formation is well seen, with its oblique bedding and numerous regular faultings, and where its fragmentary shells, corals, and other organisms can be largely collected. A hasty visit to St. Catherine's Chapel, on the knoll of Lower Greensand, overlooking the railway, the valley, and Shalford Park, ended the expedition, which, favoured throughout with glorious sunshine, now broke up, amidst congratulations on a successful day and a happy meeting of mutual pleasure and instruction, with a hearty desire to meet again in that beautiful county under the guidance of the same good leaders.-Mining Journal, June 12, 1869.

CORRESPONDENCE.

DISCOVERY OF DIAMONDS, ETC., AT THE CAPE.1 SIR,-Having read in your May (1869) Number, p. 208, Dr. Atherstone's reply to my article (printed in the GEOL. MAG. Vol. V. p. 558, for December, 1868), entitled "Diamonds from the Cape of Good Hope," allow me to add a few words in rejoinder.

And, firstly, Dr. Atherstone says (p. 209), "As it was mainly through me that this accidental discovery was brought to light . . . I am therefore, by implication, accused of being one of the impostors in this fraudulent bubble scheme,' "-allow me to assure Dr. Atherstone that I did not intend in any way to implicate him, or indeed any one personally as acting designedly to mislead; my motive (whatever Dr. Atherstone or the Cape Newspaper Editors may insinuate to the contrary) was honestly to caution the scientific-and through them the public at large-against placing implicit reliance upon the newspaper reports sent home from that colony respecting these wonderful diamond discoveries, which, if not altogether without foundation in fact, were at that time, to say the least, grossly exaggerated statements.

Secondly, the same writer states (p. 213), "Mr. Gregory told me his object was not to search for diamonds but for Nickel and other minerals usually found associated with them," etc. I admit that I said I might look for Nickel minerals, but I deny most emphatically having said that I was going to search for Nickel and other minerals associated with diamonds, as Nickel ores are never found associated with diamonds. Indeed I am quite certain that not a single person in Cape Colony had any idea of the real object of my visit (whatever they may now assert to the contrary) until the appearance of Mr. Emanuel's letter in the "Journal of the Society of Arts" informed them, and subsequently my own article in your MAGAZINE already referred to. In matters of this kind I have learned to keep my own counsel.

Thirdly, as to my geological observations-(1) That with the knowledge we at present possess of the diamond-bearing rocks in

1 This letter was sent for publication in the June Number, but we were compelled to postpone it, with other matter, from want of space.-EDIT.

other parts of the world, we are led from the geological character of that part of the country to consider it impossible that any diamonds could really have been found there: I must beg still to hold to that opinion-first, because Dr. Atherstone himself has no direct knowledge of the district referred to, nor, secondly, of the exact places where the diamonds were really found; and, thirdly, because Dr. Atherstone told me himself that he did not know much about Geology, but that his son was a pupil of Professor Tennant's, and he was therefore interested in Geology. (2) As to my silence regarding the presence of Dicynodon remains: I was quite aware of their occurrence a few miles south of Cradock, and saw many specimens when at Dr. Grey's, of Cradock, but not any "beautifully perfect reptilian and other fossils" (vide p. 211), as stated by Dr. Atherstone; indeed these remains are always in a very fragmentary condition, by reason of the indurated and unworkable nature of the matrix in which they are contained. But south of Cradock does not mean the whole district in a direct line from Cradock to Hopetown-which is what I stated in my paper (GEOL. MAG. Vol. V. p. 558).

It should always be borne in mind that Geology, like many other sciences, is not infallible, and that it is quite possible that diamonds may be found in rocks where past experience has taught us they never occur, but still we find the maxim experientia docet usually holds good in diamond-prospecting as well as in that for gold.

2

Fourthly, Dr. Atherstone's statement (p. 212) that, from a sight of a "photograph and plaster-cast," which he showed me, I " at once pronounced an opinion as to its quality, declaring it to be a 'boart' diamond of very little value," needs correction. What I really said was that, from the multitude of striae on the imperfect faces of the dodecahedron (the form of which I could distinguish), I was led to conclude that it was not of first-rate quality; as to its value I gave no opinion whatever.

I could have wished (did space permit) to call attention to many grossly incorrect statements which have been printed in the Cape newspapers, both as to the diamond discoveries and also in reference to myself; but the proverb says, "passion is ever the enemy of truth." Both diamond and gold manias have affected this Colony, although, happily, the gold-fever is to some extent allayed by the fact that the precious metal has not hitherto been found in paying quantities. With the past year's experience, it is now hardly necessary to say to investors, "at all great bargains pause awhile." JAMES R. GREGORY.

15, RUSSELL STREET, COVENT GARDEN, LONDON, May 20th, 1869.

1 All Dr. Atherstone's information (as may be seen by a reference to his article in the May Number, pp. 208-213), is obtained from the statements made by Dutch Boers, natives, farm-labourers, women, and children; and he does not appear in any single instance to have visited any reputed diamond region, so that at present we are no nearer than we were last year to the actual locality whence the diamonds announced were derived.-J.R.G.

2 Mr. Sorby's recent paper, read before the Royal Society, suggests quite a new theory as to the formation of diamonds, and deserves careful attention; but little is known of the origin of diamonds or their parent rock, so that we must not entirely put aside the old theory for the new.-J.R.G.

ON A SECTION OF THE GAULT AND LOWER GREENSAND, AT LOWER FETTLEWORTH, SUSSEX.

SIR,-The papers by Mr. Judd on the Speeton Clay, and the Rev. T. Wiltshire on the Red Chalk of Hunstanton, which have recently appeared in the Quart. Journ. of the Geological Society, suggest my sending for publication the accompanying sketch of a section exposed in a cutting of the Petworth Railway, near Lower Fettleworth, Sussex, exhibiting the occurrence of a blood-red bed in association with Gault, and probably on the horizon of the Red-rock of Hunstanton and Speeton.

The section, which is from forty to fifty feet deep, exhibits four well-marked subdivisions.

The peculiar clear red of anhydrous sesquioxide of iron is rare in the British Cretaceous rocks, and notably distinct from the yellow and orange tints pervading the Lower Greensand. The red band c, like the red rock at Hunstanton, abounds in small quartz pebbles, held together by the ferruginous matrix.

Is it possible that it may be the southern extension of the red rock of Hunstanton and Speeton, expanded to six or seven feet thick at Hunstanton, and further north to thirty feet at Speeton? The Gault does not seem to have any certain representative in the north. The position of the Fettleworth red bed at the top of the Lower Greensand agrees with that assigned by Mr. Wiltshire for the Hunstanton red-rock overlying the "Carstone," and is not inconsistent with the horizon suggested by Mr. Judd for the Red Chalk, south of Speeton, resting unconformably on beds supposed to be the equivalent of the Upper Neocomian.

The intercalation of a thin red band, largely composed of anhydrous sesquioxide of iron, between beds of such different physical character, is difficult of explanation. The line of demarcation is remarkably definite, no gradation existing between the red stratum and the Gault above or the Lower Greensand below.-GEO. MAW. BENTHALL HALL, BROSELY, May 28th, 1869.

SINGULAR SUBSIDENCE AT MARTON.

SIR,-In reply to Mr. J. W. Wilson's description of a singular subsidence at Marton, near Northwich, perhaps I may be allowed to remark that the phenomenon is not so rare as may be imagined. When living in Cheshire I frequently heard of similar subsidences taking place. These occurred in every instance on the Keuper formation, and I attributed them to the dissolving away of a good portion of the rock salt, which frequently attains a thickness of nearly a hundred feet, by the percolation of running water. Considering the vast quantity of solid salt held in solution by the brine springs, this can hardly be wondered at. I do not think, however, that the subsidence of the surface usually takes place so suddenly. As a rule it will be in the ratio of the dissolution of the underlying rock-salt beds. It has frequently struck me that some of the small "Meres” in Cheshire have originated under similar circumstances. In Norfolk we frequently have subsidences of the surface by the dissolution of chalk by sand-pipes. In many parts of Lancashire and Staffordshire the surface of the country sinks where mining operations are carried on. This is best told by the great depth of the neighbouring canals, whose banks have had to be built up in order to preserve the level of the water. Near Dukinfield, the canal is in many places over twelve feet deep-the depth being a good index to the amount of subsidence undergone in consequence of the coal having been worked underneath. Newspaper paragraphs relating the sudden sinking of small areas are not rare in Norfolk, the usual vulgar explanation of them being of course earthquake action. Rock salt is much more readily soluble than Chalk, so that it is very probable the subsidences in Cheshire and Norfolk are due to the similar action of water in dissolving and removing the solid matter of the strata beneath. J. E. TAYLOR.

NORWICH, June 13, 1869.

MISCELLANEOUS.

A GIGANTIC OOLITIC LIZARD.-Prof. Phillips has lately recorded the discovery-in a quarry at Enslow Bridge, a few miles north of Oxford-of the femur of a monstrous lizard of the Oolitic age, measuring five feet and a third (sixty-four inches) in length, and 44-25 inches round the distal extremity; while the breadth at the upper end (taken obliquely) is 20-75 inches, and the circumference 46.0 inches. A similar bone (but not nearly so large) in the Oxford Museum was referred by the late Hugh E. Strickland to Prof. Owen's genus Cetiosaurus, to which genius no doubt this gigantic femoral belonged.