259

THE RAISED BEACH AND RUBBLE-DRIFT AT ALDRINGTON, BETWEEN HOVE AND PORTSLADE-BY-SEA, SUSSEX. WITH NOTES ON THE MICROZOA.

By FREDERICK CHAPMAN, A.L.S., F. R.M.S.

(Read J une 2nd , 18gg.)

I.-INTRODUCTION.

HE Raised Beaches of the Sussex Coast have been the T subject of many valuable papers and memoirs, such as those by Mantell, Murchison, Dixon, Godwin Austen, Prestwich, Clement Reid, and oth ers. So far, however, these deposits of the South Coast have never been systematically investigated for their microzoa. The minute organisms from the Raised Beaches and Estuarine Clays of Scotland and Ireland, which are of later date than similar deposits of the South Coast, have been studied and well described by G. S. Brady, Crosskey, R obertson, J. Wright, and oth ers. In the South of E ngland, we have merely a few species of Ostracoda and Foraminifera recorded from the Raised Beach and" Head " of Portland Bill and Chesilton ;* and some Foram­ inifera from a Beach Deposit in Goodwood Park, Sussex.f From the Raised Beach at Portland Bill, Gwyn Jeffreys determined Miliolilla semtnuium and a species of Cythere ; t and to these Prof. Rupert Jones has added Po()'stome!la striatopunc­ tata and a Cythere sp. nov.P j] From the angular rubble-bed at Portland Bill, Mr. Etheridge reports" 01'ris striatopuuctata and C. legulIle1l or fas cleula/Il."§ At Che silt.on two species of Ostra coda were found in the Rubble or "Head," viz., Cypris [Scot/ia] brownialla and Candona candida. Also Foraminifera (not specified). ~r From the marine sands in a sand-pit at the S.E. corner of Goodwood Park, Sussex, Prestwich has recorded the occurrence of the following foraminifera: ** Truncatula [Trzmcatulina] lobatula, Rosalina [Rota/illJ beccarii, and Nonioninll asterigerina [?], as determined for him by Messrs. Jones and Parker. In the same bed of sand these additional fossils occurred: Mvtilus edulis,

• Prest wich, Quart. Iourn, Geol. Soc. vol, xxxi (1875), pp. 33, 34, 37, and 3g. t I dem, ibid. , vol. xv (18Sg), p. ZIg. :t Ide m, ibid., vol, xxxi, p. 33. II / dem, ihid., vol. xxxi, p . 34' § I dem , ibid ., vol. xx xi, p. 37. ,[ dOH, ioid., vol. xxx i, p. 39. •• I dem , "p. cit., vel. xv p. 219. NOVEMBER, 1899.] 260 FREDERICK CHAPMAN ON THE RAISED BEACH

Cardiu»: edule, Pholas dactylus [?], Purpura lapillus, Balanus oorcatus, and Echinocyamus pusillus. Having lately had some opportunities for examining a good section of the Raised Beach exposed in a sand-pit between Hove and Portslade, I collected material from various levels, to investigate with the microscope, and was rewarded by some very interesting results, which seem to throw additional light on the history of these particular deposits. When Mantell described the Raised Beach and Elephant-Bed in the neighbourhood of Brighton,* the sections exposed along the coast to the east of that town were much more extensive than now. Beyond Black Rock there stili remains, however, a great part of the exposure of the Pleistocene deposits so well depicted by that author. On the west of Brighton, by way of Hove, Portslade-by-Sea, and Southwick, the Raised Beach and Rubble-Drift, although not of so great a thickness as to the east, is also clearly seen in the various sand-pits and cliff-sections. The cliff section towards Hove from Brighton, where the superficial beds sink almost to the level of the present beach, was described in some detail by Sir Roderick Murchison in 185 I.t He also records finding Mytilus edulis and Littorina littoralis (= L. obtusata) in the Raised Beach there. In his classical paper on the Raised Beaches of the South of England, Sir Joseph Prestwich gave a diagram section of the brick-pit near Portslade Railway Station; t and this agrees gener­ ally with the sections given below (see Figs. I and 4), which I took from the exposures in the sand-pits on the coast at Copperas§ Gap, within 36 yards of one another and almost due south of the Rail­ way Station. In these sections it will be seen that the thickness and general character of the Rubble-Drift vary considerably within short distances, owing to the Drift having been deposited in furrows running nearly due north and south, from the hills to the sea, a structure which can be well seen on reference to the I-inch Drift map of the Geological Survey. The manner of the deposition of these superficial beds upon the Chalk is shown in a section given by Prestwich, II from the coast at Southwick to the Downs north of Portslade. In the excavation in the sand of the cliff which I saw at Cop­ peras Gap, the Chalk was not exposed, but it cannot be more than a few feet below the bottom of the pit, for it appears on the foreshore.

*" Fossils of the South Downs." PIs. IV and V. Also" Medals of Creation," 2nd ed. 1854, vol. ii, pp. 8S2~858. . t Qua,.t. /ourn. Ceol. Soc., vol, vii, p. 367. t Quart. J ourn. Geol. Soc.. vol. xlviii (1892), p. 270, Fig. 4. ~ In the r-inch map spelt " Coppard's." II o». sulra cit., PI. VII, Fig. 2. AND RUBBLE-DRIFT AT ALDRINGTON.

n.-THE RAISED BEACH AND ITS MICROSCOPICAl. CONTENTS. A. T he tied of White Scllld. Commencing at the base of the sections exposed, a short distance to the east of Copperas Gap (FIg. 2), there is a thickness of about 12 to 16 ft. of fine whitish sand, with a few scattered flints, large and suhangular. Thi s bed of sand shows marked evidence of current-action, which increases towards the top. The uppermost 10 inches is of a ferruginous colour, and is inclined to become laminated. Throughout the white sand-bed, but more

Brick-earth with few Flints. (3 ft .)

F linty Brick-eart h (2ft. 6 in.), passing into

Chalk and Angular Flint R uhb lc. (IS ft.)

Layer of larg e, well-rounded Flin ts embedded in Brown Clay-Ma rine Shells. (4 in.) Ferruginous Sand. Fine current- bedded Sands with Mollusca, Ostracoda and Foraminifera. (12 ft.)

Concretionary Sandstone. (To bortom c f pit.)

F IG. I .-SECTION OF TH E R AI SED B EACH AN D R UBBLE­ DRIFT AT COP PER AS GAP. especially towards the upper part, numerous shells are found dis­ posed in narrow bands. They are chiefly of one species, Eittorina obtusata , Gmelin. Numerous fragments of Alytilus edulis, L., and a small example of Purpura lapillus, L., were also found . One of the subangular flints, measuring 4t x 3t inches, was encrusted with the barnacle, Balanus crenatus, Bruguiere. In parts of this sand-bed concretionary sandstone occurs along the plane of bedding, in pieces varying from an inch to three or four feet in length, and from the thickness of stout cardboard to about an inch ; sometimes tabular, but often elongated and in grotesque tuberous shapea." The percentage of carbonate of lime in a sample of this concretionary sandstone was found to be as much as 41"3. Where the shell layers are found the concretionary sandstone is rare or only in thin paper- • Tabular and concretionary sandstone also occurs in the sand-pit at the S.E. corner of Goodwood Park, and in th e Raised Beach at H ope's N ose, E. of Torqu ay; a t hota of the se localities its origin may be due to the same conditions as those described ab ove, FEBRUARY, I900.] 20 262 FREDERICK CHA PlIIA N ON T H E RAISED REACH

like seams; but where the sandstone-layers are best developed no shells are found . It may therefore be reasonably supposed that the shell-bands were the source of the CaC03 which forms the cement around the grains of the sandstone. When we examine a thin section of this sand stone the grains are seen to consist mainly of sharply angular quartz, with a few rounded grains of the same mineral, and angular chips of flint in less proportion ; some felspar and other mineral fragments, as

'\ I I I r" I ) a b

c B

J

F IG. 2.- THE R AI SED B EACH AND R UBBLE-DRIFT AT A LDRINGTON, NEAR B RI GHT ON. A.RUBBLE-DRI FT . B. R AISED BEACH. a. S IIINGLE B ED. h. F E RRUGI NOUS SAND. c. WHITE M ARI NE SAND WIT H C ONCRETIONS. well as glauconite casts of foraminifera, and broken sponge­ spicules, the two last being derived from the adjacent Chalk. The whole of the grains thus cemented together are separated from one another by an even area of calcite (see Fig. 3). It may be assumed that in its early stage this deposit of CaC03 around the grains was in the form of aragonite, and that this, the unstable form of carbonate of lime, has since passed into the fixed form of calcite. From this and many similar occurrences, such as the oolitic limestones with a crystalline groundmass, it is natural to suppose that the granules, although lying at first in contiguity with AND RU BBLE-DRIFT AT ALDRINGTON. one another, in the Joose cond ition of sand, have been afterwards spaced out, as it were, by the insinua tion of the concreting substance. Dr. C. G. Cullis, F.G.S., has also formed the same opinion regarding similar structures in the purely calcareous rocks forming the atoll of Funafuti. The samples of sand taken for microscopical examination were obtained from the upper part of the bed, amongst the shell-layers with Littorina. T he assemblage of Ostracoda found here is remarkable for its mixed character. It comprises, besides some recent species of marine Ostracoda which naturally live near the shore-line, two species derived from the Wealden, seven species from the Chalk, and one from the Tertiary beds. In addition to these there are numerous well-pre­ served forms of recent Ostra­ coda which inhabit streams and pools at the present day ; and which must have been transported to where they are now found, in the gentlest manner, seeing that, although so fragile, they are in many cases un ­ injured.

The OSTRACODA which I have found in the thick bed of sand of the FIG. 3.- THIN SE CT IO N OF CONCRE ­ TION A RY SA ND STO NE FR OM T HE Ra ised Beach near Portslade RA ISED BEA CH . are as follows: Species found inhabiting Streams, Ponds, and Marshes : I. Cyclocypris lcevis (MUller); rare. 2. II serena (Koch); I specimen. 3- E rpetocypris reptans (Baird); I specimen. 4. Pn()flocypris serrata (Norman); fine specimens, fairly common. 5. Ilyocypris gibba (Ramdohr) ; frequent. 6. " bradyi, G. O. Sars ; rare. 7. Candona candida (MUller) ; rare. 8. Limnicythere inopinata (Baird) ; I specimen. Marine Species indigenous to the RAISED BEACH. (Those marked N. are of northern habi t.) I. Cythere 7Jillosa (G. O. Sars) ; frequent. 2 . " lutea, MUller ; very common. 3. " concinna, Jones ; rare. N. 4. " angulata, G. O. Sars ; rare. N. 264 FRE.DERICK CHAPMAN ON THE RAISED BEACH

5. Cythere jinmarchica (G. O. Sars); I specimen. 6. " latissima (Norman); rare. Species derived from the WEALDEN: I. Cypridea tuberculata (Sow.); I specimen. 2. " valdensis (Fitton). Species derived from the CHALK: I. Bythocypris silicula (Jones); I specimen. 2; Bairdia subdeltoidea (Munster) ; I specimen. 3. Cythereis ornatissima (Reuss), var. nuda, J. and H.; I specimen. 4. Cytheropteron concentricum (Reuss); I specimen. 5. Cytherella obovata, Jones and Hinde; rare. 6. " muensteri(Romer); I specimen. 7. " ovata (Romer); I specimen. Species derived from TERTIARY BEDS [?Woolwich and Reading Series] : I. Cytheridea muelleri (Munster); I good specimen.

The FORAMINIFERA found in the sands of the Raised Beach are also of a mixed character, being both derived and indigenous. The derived species are all more or less well-known Chalk and Gault forms, and the indigenous species are similar to those found on fine sandy shallow bottoms around our coast at the present day. The Species of FORAMINIFERA presumably contem poraneous with the RAISED BEACH are as follows I. Gaudryina pupoides, d'Orb.; rare. 2. Truncatulina lobatula (W. and J.); rare. 3. Pulvinulina exigua, Brady; I specimen. 4. Rotalia beccarii (L.); frequent. 5. Nonionina asterizans (F. and M.); I specimen. 6. " boueana, d'Orb.; I specimen. 7. Polys/omelIa striatopunctata (F. and M.); very abundant. 8. " macella (F. and M.); frequent. The derived FORAMINIFERA, apparently from the CHALK and GAULT, are as follows: I. Haplophragmium nonioninoides, Reuss; I specimen. 2. " agglutinans (d'Orb.); I specimen. 3. Ammodiscus incertus (d'Orb.); I specimen. 4. Gaudryina dispansa, Chapman; I specimen. 5. Bulimina affinis, d'Orb.; I specimen. 6. " variaNlis, d'Orb.; rare, large specimens. 7. " brevis, d'Orb.; rare. 8. Bolivina strigillata, Chapman; rare. 9. Pleurostomella obtusa, Berthelin; I specimen. 10. Frondicularia archiaciana, d'Orb. ; a fragment. I I. Flabellina rugosa, d'Orb.; I specimen. 12. Cristellaria scitula, Berthelin; I specimen. AND RUBBLE-D RI FT AT ALDRINGTON.

13· Cristeliaria cultrata (Montf.) ; rare. 14. Globigerina margiuata (Reuss); frequent. 15· Truncatniiua ungeriana (d' Orb.); frequent. 16. " refulgem (Montf.) ; rare. 17· Anamalina ammonoides (Re uss); common. 18. Pulvimd ina eiegans (d'Or b.) j I specimen. 19. " haidillgen 'i (d' Orb.) ; rare. 20. " micheliniana (d' Orb.) ; common. 21. R otalia exsculpta, Reuss ; common. 22. " so/danii, d'Orb.; I specimen. The presence of the derived Chalk Ostracoda and Foraminifera is easily accounted for, since they are obviously the result of the disintegration of the Chalk beds which con stituted the cliffs at the time of the formation of the Raised Beach. The freshwater species of Ostracoda were in all probability carried down by the streams which drained the more or less flat surfaces near the coast, and it is worth the consideration whether these remains of freshwater Ostra­ coda do not point to the former existence of outliers of Lower Tertiary beds, which, being impervious, would furnish the requisite conditions of a wet and marshy subsoil. That such a superficial bed did formerly exist here about the period of the formation of the Raised Beach is highly probable from corresponding evidence elsewhere along the South Coast, and especially so with regard to' the overlying Rubble Drift. Should this not have been the case it would be difficult to understand the presence of marsh-loving species, which occur in such frequency, where, at the present time , there is little imp ervious material resting on the Chalk.«0 Another somewhat difficult problem meets us in the presence of two species of Wealden Ostracoda in the Raised Beach deposit. The nearest outcrop of the Wealden beds at the present time is in Pevensey Bay j but it is more probable that the minute cara­ paces mentioned may have been brought down by a river draining th e Weald, such as the river Adur, debouching at Kin gston-by­ Sea.r or the river Ouse at Newhav en. The Tertiary spec ies of Cytheridea was most likely deri ved from an outlier of the Lower T ertiaries. It is interesting to note in relat ion to the derivation of the introduced species of the Ra ised Beach, that Prof. Prestwich refers] in a similar way to the presence of fragments of the fossiliferous Middle-Purbeck rock s in the Head or Rubble-Drift of Portland Bill. These rocks are not now found ill situ on the Island. Similarly, thes e fragile fossils are here pres erved as remnants of pre-existent strata. * A similar case is that of the occ urrence of land and marsh shell s with Ost racoda suc h as Scottia bnnvniana and Candona candida in the Rubble at Cbesilton, ab out which P rof. P restwich has remarked U There may ha ve been a piece of mar shy ground or a pond in the Ki meridge C lay here, previously. " Quart. /ourn. Geol. S oc., vol. xlviii (1892), p. 278. t The River Ad ur wit hin recent kn owledge flowed ou t a t a point Dearly opposi te Portsl ade-by-Sea , ~ Quart. jour". Geol. Soc., vol. xxxi (1875), p. 36. 266 FREDERICK CHAPMAN ON THE RAISED BEACH

The area in which this sand-bed of the Raised Beach was laid down may have been slowly subsiding and filling up, since the condition of the deposit remains the same throughout, and the shells are littoral species. B. Topmost bed of RAISED BEACH, with Shingle layer. The uppermost four inches or so of the Raised Beach between Hove and Portslade differs much in character from the under­ lying stratum, and will here be considered separately. It consists of a layer of large, well-rounded flint pebbles, often measuring three or four inches in their longest diameter, embedded in a rich brown sandy clay. One notices, when picking these pebbles out of the clay, that they are resting directly on a shell­ bed, and fragments of the shells adhere to the under surfaces of the pebbles. The greater part of the shells forming this layer are jl1jtilus edulis; and Cardium edu/e is occasionally found with them. '*' The shells of Mjtilus found here are extremely fragile, and it is next to an impossibility to extract them entire. The reason of this is owing to the partial dissolution of the shell. In Mjtilus the shell consists of an inner layer of aragonite which readily dissolves, and an outer layer of the more stable calcite. In the present case only the outer shell-layer remains; and since this is of a granular texture, the shell is extremely friable. A similar case was pointed out by Dr. Sorby in his most perspicuous address to the Geological Society in r879,t when he described a like condition of the shell of Mytilus in the Raised Beach at Hope's Nose, Torquay.j The brown clay, when washed, yields a residuum of dark-brown sand containing a large proportion of the heavier minerals; and amongst these I have detected four which are often found in fine arenaceous clays. They are zircon, very abundant, some sharply crystalline, others with the edges of the crystal rounded. and with numerous inclusions; also tourmaline, rutile, and kyanite. The washings from the brown clay also contained, in the lighter portion, many species of Foraminifera and one Ostracod. No derived forms were found in this layer, although they are so common in the beds immediately below and above. This clearly shows that during this stage of deposition there was an entire cessation of the fluviatile influences which previously brought down Cretaceous microzoa and living freshwater Ostracoda from the land behind. The Foraminifera are all very minute, with the exception of Polystomella striatopunetata. The solitary valve of the Cythere found here is very thin and partially dissolved, so that the superficial puncta are marked by distinct perforations. * I am indebted to the Misses Constable, of Portslade, for much help in obtaining mollusca from the Raised Beach. t Quart. I ourn. Geol. Soc., vol. xxxv (,879). p. 65. :t: Mr. A. Bell, who has examined the mollusca for me, writes that "this fragile con­ dition of the Mytilus shell is not common, and I have only previously met with it at Shoreham and a few other localities," AND RUBBLE-DRIFT AT ALDRINGTON.

Contemporaneous OSTRACOD from the Brown Clay, top of RAISED BEACH. Cythere lutea, lV.~iil1er. Contemporaneous FORAMINIFERA from the same bed. I. Bulimina elegantissima, d'Orb.; 1 specimen. 2. Bolivina punctata, d'Orb.; 1 specimen. 3. " dilatata, Reuss; 1 specimen. 4. " plicata, Reuss; common. S. " textilarioides, Reuss; frequent. 6. Uvzi?;erina an/iulosa, Williamson; 1 specimen. 7. Patellina corrugata, Will.; 1 specimen 8. Discorbina giobularis (d.'Orb.); 1 specimen. 9 ., rugosa (d'Orb.); I specimen. 10. Trzmcatulina ungeriana (d'Orb.); rare. 1 I. " lobatula (W. and J.) ; rare. 12. Pulvinulina repanda (F. and M.), var. concamerata (Montagu); rare. 13. Rotalia beccarii (Linne); 1 specimen. 14. Nonionina boueana, d'Orb. ; common. IS. Polystomella striatopunctata (F. and M.); very common. From the evidence of the included shells, this bed indicates slightly deeper water conditions than the bed of sand previously described, and was probably deposited at such a depth as to be always below the lowest tide. The rolled pebbles may have been moved to their present resting-place on the mussel bed by a sudden change in the set of the currents.

IlL-THE HEAD OR RUBBLE-DRIFT. The thickness of the Head at Portslade and Hove, and indeed wherever met with, is extremely variable. Within a few yards, as will be seen by comparing Figs. 1 and 4, there is a dif­ ference of 6 ft. At Portslade it is almost uniformly composed of angular flints embedded in a loose, chalky matrix. For com­ parison, we may notice that the Elephant-bed to the east of Brighton, which is a local development of the Rubble-Drift, contains less flinty material in the upper part, and in some places appears as a loose, chalky sand of a whitish or yellowish-brown colour; it is largely composed of small chalk pebbles of every gradation in size, from minute grains up to pebbles many inches in diameter. At Copperas Gap, between Hove and Portslade, one of the cliff-sections shows a variation in the nature of the Rubble-Drift, where a lenticular seam of fine, chalky material occurs, strongly flexed or even contorted, such as would lead one to ascribe its origin to ice- or frost-action. The material of which it is composed, consists of a nearly pure foraminiferal sand, derived from the Chalk, and is comparable in many respects with 268 FREDERICK CHAPMAN ON THE RAISED BEACH the Elephant-bed at Black Rock. This seam is very different from the enclosing drift, which is a coarse rubble of angular flint and chalk. When a portion of this finer rock was dropped into a vessel of water, it immediately crumbled down into a fine powder with a few chalk pebbles and a little suspended material. The fine sandy residue consisting of Chalk foraminifera is in such a clean condition as would be almost impossible to obtain by mechanical means when treating ordinary fresh chalk for the purpose of extracting the shells. To account for this perfect disintegration of the rock, it can hardly be ascribed to any other agency than that of an alternation of frost and thaw. The" chalk detritus" of Charing, in Kent, which is found at the foot of the { . Brick-ear th. (3 ft.)

Angular Ruhble. ,

Lenticular pa tch of line Chalk H.UbhIC' 19 ft. Angular Rubble. J Rounded Pehble, in Clay. (4 in.)

OSTRACODA from a lenticular chalky Seam in the RUBBLE­ DRIFT near PORTS LADE. CRETACEOUS S1'1'. I. Cythereis spinicaudata, Jones and Hinde. 2. " lonsdaleana, Jones. 3· " ornatissima (Reuss), var. striata, J. and H. 4· Cytheridea peiforata (Romer). 5· Cytheropteron concentricum (Reuss). 6. " umbonatum (Will.), var acanthoptera (Marsson). AND RUBHLE-DRIFT AT ALDRINGTON. 269 7. Cytherella ovata (Romer). 8. " obovata, Jones and Hinde. 9. " muensteri (Romer). 10." williamsoniana, Jones.

A RECENT FRESHWATER OR BRACKISHWATER FORM. I I. Cypria lcevis (0. F. Muller).

FORAMINIFERA from a lent icular chalky Seam In the RUHBLE-DRIFT near PORTSLAD E. I. Textularia globulosa, Ehrenberg. 2. " troehus, d'Orb. 3. Il eoniea, d'Orb. 4. SPiropleda pnelonga (Reuss). 5. Verneuiiina spinulosa, Reuss. 6. Bulimina affinis, d'Orb. 7. " pupoides, d'Orb. 8. Il murchisoniana, d'Orb. 9. " brevis, d'Orb. 10." preslt~ Reuss. 11. Bolivina deeorata, Jones. 12. Lagena striata (d'Orb.). 13. N odosan'a tenuieosta, Reuss. 14. " obscura, Reuss. IS. Frondicuiaria angulosa, d'Orb. 16. Rhabdogonium tricarinatum (d'Orb.). 11. Marginult"na elongata, d'Orb. 18. Flabellt'na rugosa, d'Orb. 19. Cristeiiaria navicula, d'Orb. 20. ,. triangularis, d'Orb, 21 ." planiuscula, Reuss. 22. " lituola, Reuss. 23. " gaudryana, d'Orb. 24. ,. convergens, Born. 25. " rotulata (La m.). 26. " subalata, Reuss. 27. R amu lt"na aadeata, Wright, 28. Globigerina marginata (Reuss). 29. Truncatulina lobatula (W. and J.). 30. " "var. variabilis, d'Orb. 3I. " ungeriana (d'Orb.). 32. " akneriana (d'Orb.). 33. Anomalt"na rudis (Reuss). 34. " ammonoides (Reuss). 35. " complanata, Reuss. 36. P ulvinulina haidil1gerii (d'Orb.). 37. " mtcheliniana (d'Orb.), 38. " karsteni, Reuss. 270 RAISED BEACH AND RUBBLE-DRIFT AT ALDRINGTON,

39. Rotalia exsculpta, Reuss. 40. " soldanit' (d'Orb.), var, nitida, Reuss. Derived Chalk FORA MINIFERA from the ELEPHANT-B ED (Rubble-Drift) at BLACK ROCK, near BRIGHTON. 1. Verneuilt"na spinulosa, Reuss. 2. B ulimina brevis, d'Orb. 3. Anomalina ammonoides (Reuss). 4. Puivinulina micheliniana (d'Orb.). 5. " elegans (d'Orb.), 6. Rotalia exsculpta, Reuss. Prof. Prestw ich, in accounting for the formation of the " Head," does not adm it the agency of ice-action in so recent a depos it as this, yet, notwithstanding the clear and strong evidence which that eminent writer has given us in favour of the theory of submergence, elevation, and disintegration of the prominent land-surfaces by the strong current-action due to the emergence of the land, it seems apparent from the evidence given above, that severe frosts acted, now and again, in a very marked way, concomitantly with the aqueous denudation. From the investigations of Mr. Clement Reid " and Mr. Lewis Abbottt we have no doubt of the existence of shore-ice and severe frosts at the time of the deposition of the " Mud Deposit " of Selsey, and of the Raised Beaches, and it is not unreason­ able to suppose that these conditions recurred at intervals during the formation of at least the earlier part of the Rubble-Drift. [After completing the foregoing paper on the Aldrington Raised Beach and Head, my attention was called to a paper by Mr. S. H. Warren] on the same section at Aldrin gton, which I had overlooked. Mr. Warren gives the following section, which generally accords with that given in the present paper : " 4. Surface Soil ... 1 ft. 3. Dark- coloured , stony; clay, descendi ng into pipes 6 in. to 3 ft. or more. 2. Cont orted chalky loam, a large proportion of its mass being composed of flints, often broken. and said to yield mamm alian remai ns at the base ... 10 to 12 ft. I. Lig ht-coloured sand, red in the upper part, with layers of well-rolled flint-pebbles, and many concretionary nodules, which are sometimes tubular. Marine mollusca and Balan idee fairly abundant. Mytilus ~du lt's in the pebbly layer. Natica [Littorina obtusata.], etc., in the sand. Seen to...... 9 ft." It is also interesting to note that Mr. Warren remarks on the peculiar contortion of parts of the Rubble-Drift at this spot, and suggests the probability of grounded ice having been the cause of the phenomenon.] • Quart. jount. Geo], Soc., vol. xlviii (1892), p, 347 ~t seq. t Of. cit. p, 269, footnote. t " Note on a section of tbe Pleistocene Rubb le-Drift near Portslade, Sussex." Geol. JlfaI{" 1897, PP. 302-304.