68 



NA TURE 



[November 21, 1901 



It is therefore very desirable that any new bit of evidence 

 bearln;; upon the case should be placed on record, and, from 

 this point of view, a discovery recently made at Didlington 

 Hall seems to be of value, especially as the conditions which 

 it indicates are exceptional in the district and the facies of the 

 animal remains found is unusual. The bones and shells were 

 carefully collected by Lady Amherst and are now preserved in 

 the museum at the Hall. 



Didlington Hall is built on the margin of an extensive bed 

 of Boulder Clay, into which the river has cut back, forming a 

 cliff which now rises from 26 feet, the level of the water 

 in the lake, to about 3S feet above ordnance datum. 

 It is no longer seen as a clifl just here, because the original form 

 of the ground has been much modified by natural and artificial 

 operations. Down the valley, however, this cliff forms a well- 

 marked feature along Ihi; right bank, but up stream it is generally 

 softened down into a gentle slope. Owing to the overlap of the 

 artificial soil and rainwash near the Hall, nothing was known of 

 the character of the marginal deposits of the river until, in 

 carrying out some alterations in the boat-house, it was found 

 necessary to cut off and dry a portion of the bed of the lake 

 and remove some of the clay close to the original bank. 



The lowest part of the bed was full of large stones out of the 

 Boulder Clay, most of them covered with glacial strire. With 

 them were the bones of large animals which had probably been 

 also washed in from the bank in floods. It appeared to be a 

 deposit thrown down in an embayed curve of the river, perhaps 

 even cut off from the stream so as to form a pond or " broad." 

 The velocity of the stream cannot have been great, for the rest 

 of the deposit consisted of fine blue mud and the shells were 

 well preserved, as were also the plant remains, though these 

 were very fragmentary. There w.^re, moreover, no signs of 

 sorting by water in any part of the deposit exposed, which was 

 not more than 18 inches or two feet in thickness. The 

 river must have been diverted or its velocity somehow checked 

 and this small patch left as a record of some of its latest efforts 

 in this part of the valley. 



This clay was covei-ed by a few feet of later deposits from the 

 existing lake, and was penetrated by the roots of water lilies and 

 other aquatic plants. 



The following shells were found in it and determined by Mrs. 

 McKenny Hughes :—5>/ias?-««/« Corneum, Linn., Pisidiuin 

 anniiaim, Mvill., P. fontinak, Drap., Unio sp. fragments 

 only, Bythinia tentaculata, Linn., Valvata piscinalis, MiiU. , 

 Planorhis carinatus, Miill., Limnaea feregra, Mtill. (several 

 varieties), L. aiirinilaria, Linn, (and varieties), L. stagnalis, 

 Linn., L. palustris? Mull., Siicdtiea putris, Linn., Helix 

 {Friiiicicola) hispida, Linn., H. (Xei-op/iila) Ericelorum, Miill., 

 Piifa margina/a^ Drap. The larger animals were.; — Elep/ias 

 primigenius, Eqiius caballiis, Bos longifrons. Cerviis elapkus 

 of very large size has been found in a similar deposit in the im- 

 mediate neighbourhood. 



We notice the ab.sence of the older forms of Bos, viz. Bison 

 priscus a.nd Bos Unis ; whereas a strain of Bos longijfrons occurs 

 here, though it has never been found associated with the 

 mammoth in the gravels. 



Bos longifrons has not yet been satisfactorily described. There 

 is certainly a larger and a smaller variety in the peat of both 

 Ireland and England, but whether they were wild or all domes- 

 ticated or derived from a domesticated breed is not clear. 



It may be that further search would yield some of the forms 

 whose absence we remark, but the evidence, so far as it goes, 

 points to the Didlington Clay being more recent than the gravels 

 in which the mainmoth occurs elsewhere in East Anglia. It 

 might be, of course, that it was made up of the washings of earlier 

 deposits of various age, but there is nothing in the condition of 

 the mammoth bones to suggest that they are not of the same age 

 as the other remains found here. Moreover, several consecu- 

 tive vertebra; of the mammoth found together in their natural 

 order prove that the ligaments had not perished when the bones 

 were buried in the clay. 



Some of the bones, especially those of horse, were grooved 

 and striated in such a manner as to remind one of ice action, 

 and of course the close proximity of the Boulder Clay suggested 

 the possibility of their being derived from it ; while we have to 

 bear in mind also the probability of the agency of river ice at a 

 later period. 



On the other hand, similar stria; on the bones found in other 

 sections in East Anglia have undoubtedly been caused by settle- 

 ments in the stony mass by which the gravel has been squeezed 



against and even into the inside of the bones while the process 

 of decomposition was going on. This fact and the occurrence 

 of similar stria; on the bones of saurians in Jurassic clays throw 

 great doubt upon the inference that the scratches on the Didling- 

 ton bones are due to any kind of ice action. None of the plant 

 remains have been determined. 



There is much evidence in favour of the view that after that 

 not so very remote yet very exceptional episode, in which 

 glacial conditions prevailed over this area, the whole of the 

 district stood at a higher level. Then the basin of the Wash 

 and its tributaries was re-excavated .and extended, and a con- 

 siderable resultant river found its way intothe sea through Ihechalk 

 escarpment between Hunstanton and Skegness. Into this river 

 the Wissey and other streams of west Norfolk found their way. 

 Some time later the area was depressed, and the rivers, which 

 had descended with considerable force, especially in times of 

 flood, were met by the tides at higher and higher points as their 

 valleys gradually sank to sea-level. But this was not a sudden 

 or even a rapid change, and the species of plants and animals 

 disappeared by degrees as the conditions became unsuited for 

 them. The Didlington Clay belongs to this period of changing 

 conditions and is a late Pleistocene formation laid down after 

 the arrival of Bos longifrons, but before the mammoth had 

 ceased to inhabit, or at any rate to be a visitor in, the district. 



Almost all the remains of the earlier Pleistocene times have 

 been obtained from sands and gravels of a torrential character, 

 and we have seldom had any opportunity of examining the em- 

 bayed corners where they have been preserved in fine mud. 

 This is partly due to the fact that the sand and gravel are of 

 commercial value, but the mud \% only excavated to get at 

 something below it, as, for instance, at the marl for cement, or 

 the gault for bricks, or, as in the case to which attention is now 

 called, where the excavations were made for a new boat-house 

 which exposed this blue river clay at Didlington Hall. 



But another, and perhaps the more common, reason is that 

 it was generally near the mouths of the sinking river valleys 

 which have been since submerged and buried under later 

 deposits that the velocity of the stream was checked so as to 

 allow of the deposition of fine mud instead of sand and gravel. 

 T. McKennv Hughes. 



NO. 1673, VOL. 65] 



SOME SEASONAL VARIA TIONS IN THE 

 BRITISH ISLES. 



T N a paper just published by the Royal Society ' attention is 

 ^ directed to a peculiarity in the seasonal variation of tem- 

 perature in the British Isles disclosed by the resolution into 

 hannonic components of the curves of day to day variation 

 derived from the 25-year means of the 24-hourly readings at 

 Kew, Falmouth, Aberdeen and Valencia. The peculiarity in 

 question is the second harmonic component which is repre- 

 sented by a curve with two maxima and two minima in the year. 

 In the 25-year curves for each of the observatories the maxima 

 of the second components come within four days on either side 

 of January 31 and August I respectively, and the minima are 

 in the first week of May and November. They represent a 

 temperature effect which exaggerates the height and shortens by 

 nearly two weeks the duration of the summer portion of the 

 compound curve ; it also moderates the depth and lengthens by 

 an equal amount the duration of the winter portion. The 

 effect has a range of nearly 3' F. at Kew in the 25-year mean 

 curve, out of a whole range of 24° F. Its magnitude at the other 

 stations is approximately the same fraction of the whole range 

 at those stations. It is much larger in curves for single years 

 at Kew, but the epoch varies somewhat. It is called meteor- 

 ological, as distinguished from planetary, because in the mean 

 curves for the Continental stations Vienna and Agra it is quite 

 different either in magnitude, or epoch, or both. 



An attempt is made to .account for this peculiarity by the pre- 

 valence of winds from different quarters at different times of the 

 year. The mean temperatures of 3288 successive days (nine 

 years) at Kew are grouped according to wind direction from 

 eight compass points or, more strictly speaking, according to 

 the direction at right angles to barometric gradient. The method 



1 "On lheSea«nalV.nrialion of Atmospheric Temperature in the British 

 Isles and its Relation 10 Wind-direction, with a Note on the Effect of Se.i 

 Temper.-vture on the Seasonrl Variation of Air Temperature." By W. N. 

 Shaw, F.RS., and R. Waley Cohen. Read Ijefore the Roy.-tl Society, 



