THE GEOLOGY OF THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON.
By]. F. BLAKE, M.A., F.G.S.. President. (Read July srs, I89I) H ER E are two portions of the coast of England where one can T trace a continuous succession through the whole of the secondary rocks. One of these is in the south from Studland to Axmouth, the other in the north-east from Bridlington to Redcar. The contrast between these two is great. Although the com ponent members can be more or less continuously traced across the intervening space, the final terms of the series are more remarkable for their differences than for their resemblance. Throughout the whole succession we are in the face of two distinct types. The first endeavour of the Geologist is to assign the causes which have produced so remarkable a result. If we lay before us a geological map of England, and examine the structure of the Pennine chain, we see that in its centre-on the line that runs from Morecambe Bay to Flamborough Head-the Mountain Limestone comes up to the surface, and is surrounded on the north and south by Millstone Grit. In this phenomenon we have the first indication of a transverse anticlinal. This is shewn again by the separation of the Yorkshire from the Durham coal-field, through the rising of the Millstone Grit between them. The Permian follows suit. It is almost cut off as we trace it north wards, till it expands again on the other side of the Tees. In some maps, indeed, it is made entirely to disappear. Whether it actually does so or not, it rapidly changes character, so that its development in Durham is very different from what we find south of Yorkshire. Passing to the Trias, we find the Bunter sandstones to have quite disappeared (Mem. Geol. Surv., Sheets 96 N.W., and 96 S.W.), and the Keuper beds alone continuous from the Humber to the Tees. All these facts point to an upheaval of post-Carboniferous date along this line, which has had a separating effect on the areas to the east in the immediately succeeding periods. It was this old axis of elevation, which marked off the Yorkshire area through out Jurassic times. It was, indeed, depressed during the deposi tion of the Keuper and Trias, wherever they are clays-as we should naturally expect from the depth generally required to pro duce such rocks. But in the succeeding times it operated again. The Madstone, the Inferior Oolite, the Middle Oolite, and the Upper Oolite limestones, one after another, are seen to thin away as they reach the south of Yorkshire from across the Humber, and N ,. ... 84' 1 ~U l... JK.,tAClu~A: N_ 0'1
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FI G. I. -SECTION SEEN AI.ONG TH E CO AST OF YO RKSHIRE F ROM WH ITB Y TO FIL EY BRIG.-J' . F. Bla ke. THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. II 7 the Great Oolite-even that most persistent bed, the Cornbrash dies away entirely; only the great clay deposit of the Oxford and Kimmeridge groups succeeds, as the other clays have done, in tra versing this dividing line. There was, therefore, a great physical barrier which separated the Yorkshire area throughout the whole period of deposition; and the basin thus formed was filled with material from different sources, and under different conditions from that of the larger area of the south. So much for the Jurassic rocks. Looking again at the geological map, in the area where the Trent runs eastward, we find that the Pennine chain and its ac companying Nottinghamshire coalfield come to a sudden end; and that beyond it, to the south, come great bosses of Mountain Lime stone, and the uprise of the older rocks in Charnwood Forest. This indicates a second transverse barrier, which had its first effect upon the Trias in the termination of the Bunter, and a later one upon the Jurassic in the estuarine character of the Great Oolites. But its effect was most marked in Cretaceous times; for north of this line, all sign of Gault and Greensand has disappeared, the Neocomian puts on a new aspect, and the Red Chalk begins to overlie it. The Chalk itself is tinged with red in its lower parts, and has occasional bands of clay, while the rest of the deposit is different in character, and no longer allows us to trace the persistent bands which mark off its subdivisions in the south. The basin thus bounded in Cretaceous times extends into Yorkshire, and thus its special characters are accounted for. After the abundant work that has been done upon this most interesting area by Phillips, Tate, Hudleston, the Geological Surveyors, Lamplugh, and the writer, there is little or nothing original to be said on this district, and one can only attempt to put into a connected form the knowledge already acquired. In tracing the upward succession of the rocks, we commence, of course, at the north. Here we find Triassic Marls which sweep round in a curve to the west, and form the boundary and basis of all that is interesting in the Secondary rocks of Yorkshire. Even these show a peculiar feature in the occurrence in them of a bed of rock salt 100 feet in thickness. This is found nearly at the base of the series, almost in contact with the Magnesian Lime stone, and Messrs. Lebour and Howse, of Newcastle, believe that it actually belongs to the Permian, or at least that some portion of it does. It is difficult, in fact, to say in this district where Permian ends and Trias begins, in spite of the absence of the Bunter. It may, indeed, be questioned, seeing that we have lost the Bunter, and gained in its place higher beds of Permian, whether one does not represent the other in time, the conditions of deposit having been different through their separation in different areas. However this may be, the occurrence of rock salt is interesting as indicating the physical conditions of deposit. It is not, indeed, on the same JI8 ]. F. BLAKE ON THE GEOLOGY OF horizon as the rock salt of Cheshire-which lies in the Keuper Marls, whereas this is at the base of theWaterstones-but it is an analogous formation. In Cheshire the salt forms lenticular masses, and there is every season to believe, from the sporadic nature of its occurrence, that it does so likewise in the Yorkshire and Durham area. Rock salt, from its great solubility, can only be formed where the sea either dries up or so nearly does so that the water is supersaturated. In either case the basin must be enclosed, and subject to much evaporation from its nearness to the atmosphere. This points to an elevation of the area and a cessation, for a time, of earthy deposits, and thus we find ourselves at the commencement of the formation of the Yorkshire basin. On the first commencement of depression we have the forma tion of the sandy Waterstones-thin bedded and even laminated, as though but little removed from the surface of the water; and these extend as far as the southern barrier. As the depression continues, we have the Keuper Marls widely spreading over the whole of England, and covering every older rock exposed; but still so confined beyond our area as to exclude the open sea with its abundant life. As the sea widens, the tea-green marls begin to denote a change, and with the black shales of the Rhretic we have the rash venturing of the outside forms of life into our area, and their rapid destruction as witnessed by the Bone bed. All these latter features are common to Yorkshire and the south of England. But after this, the northern barrier began to make itself felt, so that, though the sea was continuous over the whole of England, France, and Germany, during Liassic times, there are marked dif ferences in the minor lithological character between one locality and another. Commencing with the base of the Lias, we look in vain along the Yorkshire coast for any representative of the lowest zone, that of Am. planorbis. It doubtless occurs in the bottom of the North Sea, as proved by the constant washing up of hard calcareous nodules with this species (formerly called in Yorkshire Am. erugatus) in excellent preservation. Such specimens are never to be met with in the south of Yorkshire, on the other side of the dividing line. The zone is there well represented, but the specimens of Am. planorbis are more often of the slightly ribbed variety, and are flattened in the shale as in the south of England. The succeeding zones of Lias, those of Am. angulatus, Buck landi, and oxynotus, are well exposed at Redcar, and the two latter in Robin Hood's Bay. In these two localities they do not differ much in character. They present us with none of those smooth argillaceous limestones which have gained for the formation its name, but with a number of banks, each terminating upward in an indurated rough band, often filled with fossils, the most plenti ful of which are oysters of the form of Gryphea arcuata. These are very commonly small in size at the base of any particular band, THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. 119
FIG. Z.-SKETCH MAP OF ROCKS BETWEEN BLEA WYKE AND ROBIN HOOD'S BAY.-.J. F Blake. 120 ]. F. BLAKE ON THE GEOLOGY OF and grow larger towards the top, as though the whole deposit of the hand had taken place during the growth and development of a single colony. The occurrence of these lowest zones at the two ends of the Liassic area indicates a synclinal, and this is carried out through the whole of the series, so that we find the highest beds in the centre on the shore at Whitby. As the natural dip of the beds is to the south, the uprising of the older zones in that direction must be finally compensated for by an undulation or a fault. The latter is found well shewn at Peak. Either limb of the synclinal will give us the succession; and, in point of fact, by going northward from Peak to Whitby, we can trace zone after zone laid out for us on the scars, mounting in the cliffs, and giving magnifi cent opportunities for study. The angu!atus beds, with their fauna, are, however, not brought up to the surface in the south, and are met with only at Redcar. Doubtless they are really continuous, as they are well developed in the extreme south of the county. On the coast of Robin Hood's Bay, the lowest beds we can find are the seaward scars, uncovered only at low water, whence the numerous ammonites and other fossils of the Buck!andi zone may be met with in plenty.* The different members of the Lower Lias here run in a gentle curve parallel to the coast, so that the shore ward scars represent a higher zone-that of A. oxynotus. t
FIG. 3.-SHORE-PLAN IN ROBIN HOOD'S BAY, SHOWING THE POSITION OF THE LIAS-ZONES.-G. Barrow. [Compte Rendu Congo Geot, Int., 1888 (1891).J On reaching Baytown, however, the trend of the cliffs is changed, and here, in consequence, we more rapidly rise in the
* The principal fossils to be expected in these beds are- A »unonites sauzeanus. Leda galathea. Lucina limbata. semicostatus. Protocaraiwni oxynoti. Pleuromya liasina. Gry/Stea arcuata. Cardinia hybrida. Pentacrinus tuberculatus. Pecten textorius. t The principal fossils to be expected are- Ammonites densinodus. Belemnites acutus. Pecten cah-us, gagateus. Hydrobia solidula. Protocartiitnn ovynoti. saeittarius, Lima pcctinoides. THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. 121 series, and immediately encounter a marked change in the fauna, which suddenly becomes richer, and with the species distinct. G. arcuata can scarcely be recognised as the characteristic oyster, but G. Maccullochi, a more open and oblique form takes its place. Then there is a profusion of beautiful ammonites-A. armatus, A. polymorphus, &c., often yellow with pyrites, with Pinna foliulll and several bands of Pholadomya, erect as when alive. * This sudden change of fauna has seemed to Tate and myselftojustify the draw ing a dividing line at this horizon between Lower and Middle Lias. The line is thus a palreontological one and has been objected to as such. It is said to be un mappable. It is no more unmappable than similar lines in the Silurian slates or in the Chalk; or than that between the Oxford and Kimmeridge clays when the corallian is absent, or when this last is argillaceous as it is in Lincolnshire. In drawing the line of division at a higher level, Mr. Barrow, the Geological surveyor, states that his line has been adopted by the Geological Survey throughout England, and must therefore be continued into Yorkshire. This is a mistake. In Somersetshire the zone of Am. margaritatus is taken to be the base of the Middle Lias, and the same is adopted by Prof. Judd in Rut land; the base-line is continued at the same level in South Lincolnshire, so that it is very doubtful if the line is drawn anywhere out of Yorkshire on Mr. Barrow's horizon. Ours is said also to be a lithological line, because it is placed at the base of sandstones in Yorkshire. But sandstones do not occur at the same horizon throughout England; the same beds in Lincoln shire are clays, while what is clay in Yorkshire is a rock-bed else where. In fact, the palreontology is constant, the lithology is variable; and a line, if drawn by lithology throughout England, would have actually to cross the stratification. It may be locally convenient, but is generally unscientific. (See Mem. Geol. Surv., N. Lincolnshire, by W. A. E. Usher, 1890.) This divorce of palreontology from lithology is, to my mind, most instructive. It appears to give the coup-de-grace to the idea that environment alone is the prime factor in the origination of species; for the species change while the environment appears the same, and the species remain constant when the environment varies. I say advisedly" the environment appears the same," because the litho logical conditions may not make up the whole of it. When we come to examine this zone of Am. capricornus, the non-essential character of the lithology becomes still more marked, for the lower portion of it is as argillaceous as the beds below, so that a lithological line has to be drawn in the * The following is a list of the commoner fossils- A ntntonites armatus. Limea: actcticasta, Gresslya ovata jolymorphus. Gryphfa AIacculloclti. Unicardium cardioides, " !we'l'l·sjJina. Plicatuta sjJi'llosa. eucut/tea Muensteri. Belemnites elegans. Pinna/olium. R hynchonella plicatissillla. " araris, Pholadomya: decorata. Waldheimia sarthacensis: Chemrdteia Blainvillti. 8 122 j. F. BLAKE ON THE GEOLOGY OF midst of a zone.* On the north side of Robin Hood's Bay is seen a line of small, round and rather flattened doggers, almost everyone of which encloses a single specimen of the characteristic ammonite, which local collectors have on this account called " jack-in-the-box"; its allies and varieties are met with in plenty in the intervening clays. The North Cheek of the bay, however, is composed of the resisting sandstones, which form a headland, and render progress difficult. This is a sign of the shallowing of the waters, which the irregularity of the beds confirms. They are crowded with great oysters, Gryphea C)'mbium, which lie in beds, and the equivalents to the north of Whitby yield the various starfishes which make such beautiful specimens, t Compared with their thickness in northern sections, they show here a less development, indicating a probable source somewhere to the N.E. Passing the corner of the North Cheek, we are st.ill in sandy beds, but they belong to the zone of Am. margaritatus , and it is only some way up in this that we enter clays again, which are everywhere richly fossiliferous, and are finally capped by the iron stone doggers of Hawsker Bottom, which are often nothing else than a mass of shells, and form the principal part here of the zone of Am. spinatus. This zone is separated on account of its constancy elsewhere as marlstone, its importance in the north as an ironstone, and its constant wealth as a gathering ground for fossils; but it is in reality little more than a sub-zone of Am. mar garitatus. Anyone studying these beds at Hawsker alone would have quite an erroneous idea of them, for nothing is seen here which is comparable economically to the magnificent ironstone of Cleveland, or even to the thinner Avicula seam at Grosmont. Throughout the whole of the series we have a thinning to the south, indicative of a northern source, and showing the charac teristic separation of the Yorkshire basin. t Overlying the shelly ironstone doggers at Hawsker we have an admirable exposure of the Grey Shales. These we may conceive as produced by the influx of sediment from a new source, intro ducing a new type of ammonite henceforth to be predominant, but scarcely known before, the genus Stephanoceras. But so flourishing were the older types that they could not be destroyed at once, but were killed off one by one. In these Grey Shales we
* There seems to be some confusion in the minds of certain Geologists as to what a zone is. It is a set of beds characterised by the association of certain fossils. As index to the zone is often chosen an auimonire, which occurs abundantly within, but may range above or below it. t The commoner fossils at Robin Hood's Bay are- Ammonites ca.pricornus, Protocardnon truncatum. Leda minor. Dentatium gigantcum. Modiola scalprum. R hynchonetla calcicosta. :j: The commonest fossils in these two zones are- Ammonites margaritatus. Turbo cyciostonca; Astarte striatosu!cata. "spinatus. Pecten ayuivahJis. Cardinia levis. Belemnites cl auatus, lI:1onotis in(pqul7.!alz1is. P Iru ronrya: costara, CryjJtcpnia expansfl. Lcda. complanaia. R hynclzone!la tetrahedra. Fucyc!us tlJululatus. Protocnniiunr trtcncaiusu , THE COUNT RY BET WE E N REDCAR AND BRIDLI NGT ON. 123 have, therefore, a true set of passage beds, which may be alm ost equ ally well classed with tho se above or below. In th ese another " jack-in-the-box" occurs, but in this case th e ammonite enclose d is A. annulatus, This series is the introduction of a fresh depres sion, th e maximum of which is in th e north, where th e lower beds are thicker.afact which lend scountenance to the idea that, in some cases,at least, deposition is th e cause of depression . Yet the rat e of subsidence was slow, for we cannot do oth erwise than sup pose that the Jet R ock series which ~ '"~ immed iately succeeds, with its abun if> dant carbonaceous remain s, in part, at ..-e least, derived from the land , is any :r:-- th ing else than a shall ow water de ;g posit. The material of jet, however, o is not always fossil wood, though this "j..Mt~ '" has contributed largely to its forma ~ o tion. In man y cases it seems to be :I:'" a liquid segregation, which, like flint, en -e has consolidated in isolated spots. In w en the case of jet, th is has formed lent i cular patches which occur at random levels throughout th e series, and may at an y time be met with on searching. The line of its occurrence is well marked in th e cliffs, or used to be, by the old workings. The same material, when not consolidated, im pregnates the entire rock, which yields, on a fresh fracture, a bituminous smell, and , in the interior of th e chambers of the ammon ites, is still to be found in a liquid form. These rocks, and the Alum Shale above them, are the reposi tory of whole shoals of belemnites, sometimes formin g a bed, and with the ammonites constituting the commonest fossils. One of th e most remarkable of th ese belemnites is B. tubularis. In stead of terminating in a hard con ical guard, the lower end was run out into a long soft sheath, whose termination has not, to my know ledge, been observed. I believe it gradually got soft and feathered off to nothing. In addition to the bitu men, the Jet Rock is characterised by its richness in pyrites. This is do ubtless a result of subs equent change, and seems connected with the abundance of animal life. So much is this the case tha t the most pyritous band of all is kno wn to local 124 j. F. BLAKE ON THE GEOLOGY O~' collectors as the" animal dogger," from the numerous remains of fish and reptiles that occur in it. Pyrites is generally said to be insoluble in water, but there can be no doubt that this has been left by an aqueous medium. Probably the decaying organisms have reduced the sulphates, and combined the product with the iron in the surrounding rock; and here may be mentioned one of the most remarkable doggers I have ever seen, obtained from the Boulder clay in Robin Hood's Bay, but doubtless derived from the Jet Rock series. It was of a depressed spherical form, and shewed the lines of stratification on the exterior surface, but it was hollow. On breaking it open, the outside was seen to consist of a thin layer of pyrites, about three-sixteenths of an inch in thickness; enclosed in this was a mass of loose dust, gradually changing to hard jet rock in the centre. It was obvious that the cementing material had been extracted, and part of it concen trated on the surface, which must have been more or less porous during the process.* The Alum Shale does not call for much notice. It is hest seen at Whitby and in the deep quarries on the heights round Robin Hood's bay. It is much more free from doggers, and is more or less laminated. Some of the best preserved skeletons of reptiles have been obtained from it, and they are easy to work out. One of the commonest ammonites is A. bifrons, t but this has too wide a range to give its name to a zone. The highest zone of the Lias is seen only in one spot in all Yorkshire, namely, on the S.E. side of the Peak Fault-between it and Blea Wyke. Here the shales below the Inferior Oolite put on a special character, being less laminated and more friable. They are of considerable thickness as seen in the lower part of the high cliffs here, but neither their upper nor their lower limits are very well defined. Though the fauna changes, the deposit here seems to have been quite continuous from the Lias to the Oolites. The zone is called that of Am. jurensis, from the abund ance of that ammonite in other districts. The species occurs here --but rarely-and the truly characteristic form is Am. striatulus, which is abundant in groups forming nodules about half-way up the series. The whole assemblage of ammonites in these beds is rather peculiar. They can scarcely be any longer included even in the genus Harpoceras, but have been separated as Haugia, Grallllllatoceras, &c. Here, too, we meet with the beautiful
* The commonest fossils in this zone are- Ammonites cxaratws. Belemnites tubularis. hlOCeraJ11US dubius. elegans, Voitzi, Posidonotnya-Bronni. crassescens, Iauis, Pecten fund/us. gracilis. subtenuis. t At \Vhitby the common fossils are- Annuonitcs communis. Ammonites lythcnsis. Gresslya donaciforniis, crass-us, "pri11lordialis. Ledaovum. Hoiasuirei, Belemnites vU~lJaris. Monotis substriata. bifrons. iavis, Inoceramus cinctus. THE COUNTRY BETWEEN REDCA.R AND BRIDLINGTON. 125
Trigonia Iiterata, and a quantity of forms quite distinct from those of the Alum Shale, * so that it is a well marked palreontological horizon. Nevertheless it has many links 'with the Lias--and fewer with the Oolite-so that we .are justified in retaining it in the former formation; a question, however, which can be better discussed later on. Entering on the consideration of the Inferior Oolite we meet at the outset with a very remarkable phenomenon, as to the cause of which I cannot pretend to be thoroughly satisfied. Lying immediately on the Alum Shale at Whitby comes a thin band of calcareous sandstone, with comparatively few fossils, not more than three feet or so in thickness, which represents the " Dogger"; so that one can actually stand on Alum Shale and extract with the hammer blocks of the Lower Estuarine series containing ferns; this state of things continues, with little change, as far as the fault at Peak, where the same bed may be seen form ing a mural escarpment above the Alum Shale quarries. But on crossing the fault a sudden-an astonishingly sudden-change is seen. Beneath the Estuarine series of the Peak come 100 feet belonging to the Dogger and its associates-the character of which is also greatly changed, and below these again come the jurensis beds of seventy to eighty feet in thickness. Two interpretations seem possible: one is, that the Dogger of Whitby represents only the upper part of the Dogger of the Peak, and the intervening beds are wanting. This involves, first, the existence of the fault at Peak before the Dogger was deposited, which might very well be the case if we suppose it to have formed a line of weakness which again gave way at a later period, and, secondly, an unconformity between the Dogger and the Alum Shale at Whitby. Such an unconformity would be difficult to observe directly with a bed of clay below; but we may well wonder why the denudation has been so uniform that so little, if any, of the jurensis beds and lower part of the Inferior Oolite is anywhere left. On this point, however, we may cite the apparent unconformity to be noted in the northern boundary of the Lias, where the thickness of the Alum Shale varies very considerably in closely contiguous spots, the quotation by Young and Bird of Am. jurensis from Glaizedale, and the existence of the great mass of ironstone in Rosedale; this rock is neither Alum Shale, which can be recognised below, nor Dogger, which may be seen as usual above. Still this interpreta tion has its difficulties. The other explanation is that the line ot the Peak fault marks also the boundary of two regions, distinct in Upper Liassic times, so that the lacking beds were never deposited on the north. To the aid of this hypothesis comes the fact that, while the Liassic beds have uniformly thinned in * The fossils to be found here are chiefty- Asmnonites str£atulus. Leda inrequilatera. Lima toarcensis. C011(,pactilis. Venus ten-uis, lJ.1onotis substriata. variabiiis, Trigonia literata. FValdhemia Lycetti, 126 ]. F. BLAKE ON THE GEOLOGY OF going south, all the deposits of the Inferior Oolite thin in going north, and we know nothing of what the Lias does below. Against it is the problem of how the boundary comes to be so very sharp. Still worse, if the deposits were really continuous, then the thin band of the Dogger at Whitby would represent not only the lower beds of the Inferior Oolite, but also the jurensis beds. This would make the latter a part of the Dogger series, against which palaeontology, as I read it, speaks loudly. Probably a combination of the two views may best suit the case. I think there is some slight unconformity where the Dogger lies directly on the Alum Shale. There is probably also a thin repre sentative of the jurensis beds in many spots where it has not yet been definitely proved by palaeontology. Their greatest develop ment was probably in the south, and the difference at the Peak may have been somewhat accentuated by a fault. Leaving this knotty question, we may consider the special beds at Blea Wyke, known as the Blea Wyke beds. These contain a peculiar fauna, among which the little Vermetus and the Lingula Beani are most conspicuous on the spot. The ammonites, how ever, arc of the most importance for correlation. Of late years much has been done by S. Buckman in tracing the zones of this part of the series, and he distinguishes many more than Dr. Wright did. When I examined these beds I was not specially concerned with the Oolites; and the ammonites about here are so much alike that they require a very special study. I am not, therefore, prepared to defend any names that I have given; on the other hand I am sure there is still great confusion about the species. One thing is certain, the most characteristic ammonites belong to the group of Am. Murchisonce / and as ammonites seem almost or entirely wanting in the Dogger, this fact serves to correlate both with the zone of Am. Murchisonce in a broad sense. Am.opalinus is one of the same group, so that we may here recognise the zone of that ammonite also, if such a zone is to be distinguished. Moreover, I have recorded Am. Moorei from the Serpula beds, so that this zone also may be present. The other ammonites which characterise zones, according to S. Buckman, are not yet, in my opinion, clearly distinguished, and in particular Am. concavus is confusing. The name is given by him to an Oolite species, whereas I think it applies truly to the Upper Lias form, not found in these beds at all. In any case, it is abundantly clear that these beds belong to the Oolites, and must therefore be classed with the Dogger. The other fossils tell the same tale. * The Dogger of Yorkshire is remarkable, at least in this spot, for its phosphatic character. The brown earthy concretions
* The principal fossils are Ammonites Aalensis, Monolis intEqui'lIa!vis. Discina refiexa. Belemnites irregularis. Terebratula trilineata. Serpula deflexa. Geruiltia H artnzanni. Rhynchonella cynocephala. Vermetus contpresstos, Pinna cuneata. Lingula Beani. IW .S .W. (i.) [ E.N.E~ . I 7-1 ~D
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containing phosphate are very con spicuous, and may be recognised in almost every fossil. Now what is the meaning of this phosphate? It is undoubtedly derived from the des truction of animal life, and if we call to mind the localities in which it occurs, we shall very often, though not always, observe that it is found where one kind of deposit is changing to another: as where the Rhretics follow on the Trias; where the Estu- ~ arine beds, as we shall see, give place i to the marine Cornbrash ; where the co sedimentary Gault and Greensand ~ cease and the Chalk begins. So here ...; it is an indication that marine life is ~ at an end, and estuarine deposits are "i about to succeed. The rapid change (5 of environment has killed the animals ~'" off, and their dead bodies having pre- { cipated the phosphate, there are no " new forms of life to take it up. One « of the most remarkable of the fossils ~ of this bed is the Nerinaa angenda. :l It is the first time this remarkable genus is met with in this country. Doubtless it migrated here from a foreign locality where it was de veloped, but succeeded only in put ting in an appearance before it was destroyed.«' Succeeding the Dogger comes the vast mass of estuarine deposits characterised by plant remains; in the lower beds these have often com bined to form thin beds of coal, but they are most richly developed in what is known as the middle portion, more especially to the south of Scarborough at the base of the Gristhorpe cliff. These plants are mostly cycads and ferns, the former so highly characteristic of Oolitic floras. They much resemble large ferns in their general aspect, but may be immediately distinguished by their venation, which, instead of bifurcating as it does in ferns, runs in parallel lines branching out '" The fossils of the Dogger here are chietly- Nerino:a cingenda. Astarte eiegans, T'rigoriia spinulosa. Chemnitzia lineata. Ceromya bajociana. Geruiitia: tortuosa. Natica adduct-a, Opis Philllpsi. Gresslya adducta. THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. 129 from the centre stem of the whole frond, and depriving the pinna: of any midrib. Still more interesting, perhaps, are the great equiseta, E. columnare, which rival the Carboniferous calamites in size, and are found beneath High Whitby, standing erect in the laminated sandstone, the whole thickness of which must have been deposited during the lifetime of a single one. Nor did they grow slowly; the nodes on the stem are far apart, and if these were annual then several inches of sand must in many cases have been deposited in twelve months. This gives us an important indica tion of the rapidity of the formation of the rock. The whole series of these Estuarine beds is very thick, yet they may not have taken so long to form as we should naturally expect; and thus we have an explanation of the remarkable fact that all of it belongs to the Inferior Oolite, and does not represent even the whole of it. The proof of this latter statement is the occurrence in its midst of three beds containing marine fossils and more calcareous than the rest. The lowest one of these is not of much consequence. It is called the Ellerbeck bed, and lies in the midst of the lower sandstones, dying out here and there. Next above this comes the Millepore bed, so called from the abundance of a polyzoan found in it. This bed is far from constant, and yields at Cloughton many varieties of fossils, from which, however, ammonites seem wanting. This separates the Lower from the Middle Estuarines.* The next is a thicker hed, called the Grey or Scarborough Lime stone, which is best studied also at Cloughton, to the south of which, at Hundale, it yields an abundant fauna, as it does also to the south of Scarborough, and at Gristhorpe, where, striking along the shore, it may be worked at over a considerable distance. This is the bed which from its position was originally taken to belong to the Great Oolite. The general assemblage of its fossils, however, and especially the presence in it of Am. Humphresianus, shows that we are still in the Inferior Oolite, and not even at the top, for we have not yet reached the zone of Am. Parkinsoni. Above this bed there is still a vast thickness of estuarine sandstones which has been little worked, and which may contain, for all we know, some characteristic fauna, but till such is found I can see no reason for separating it from the rest.r But if so, where is the Great Oolite? Was it never deposited in Yorkshire, for the next bed we come to is the Cornbrash ? Was it the very topmost bed of the series? Did that take as long to form as the whole of the Great Oolite of the south? Or is there ... The principal fossils of the Millepore bed at Cloughton are- Lima duplicata. Pinna ctcneata, Gonioseris angulata. Ceromya bajociana. M otiioia imoricaia, Cricopora straminea. Pholadomya Heraulti. Trigonia recticosta, tIts fossils are Chemnitzia scarburgensis. Gen'z"llia acuta. ilfyacifes catcei/ormis, Ostreafia/>elloides. Modiola cuneata. Gresslya pereg-rina. Pecten lens. Cucul/rPa cancellata. Vermictdaria: nodus. Avicula braaniburiensis, Trigonia coetata. 13° j . F. BLAKE ONT HE GE OLOGY OF
E XPL ANAT IONS. D. Mar ly shales, containing , toward s the base, the larger form of B,'lemnilcs giganleus, and ind ura ted shelly masses charged with A otcula , Cardium, Iso 236 D cardia, and Cerithiton, all extremely small. Furt her up occur at in ter val s masses of compressed aviculoid shells, and at t he top a lin e of iron-stone nodules with A vicula-23 ft. 6 in., making a total of SS ft. C. T he up per an d principal fossiliferous zone, consisting chiefly of hard grey marl s an d limestones, with Trigonia costata (Sow.), Perna ""gosa, Ostrea jlahelloides (Lam.), Pinna cuneata; Gervillia acuta , Avicula h"aamhu rirnsis, and t he shorter form of B elem r; 4! nites giganleus- t 3 ft. '" r 1.!'_ . ~ 12 4 B 10 ----- B. Th e great Scar Limestone, with its "O'l~]; underlying mudstones, &c.- r2 ft. 4 in. A. The lower fossiliferous zone. cha rac , " II 6 3 I'D terised by Cucul/tl'a canal/ala, C. r 10 reticuiata , Pteroperna plana, a small :', variety of Pecten lens, and , toward s the SS' J" base, by great numb ers of myaci form she lls-6 ft. Great San dstone of Middle Series. F IG. 7.-SECT ION 01' S CARllOROUGHL IMESTONE AT H UNDALE. W . H . H udleslon, F. N .S. [Proc. Ceot. Assoc., vol. iii. , p. 312.] really an hiatus? Of this latter we have no sign-the Cornbrash succeeds with regul arity and there is no unconformity. The only suggestion I can make is that the Es tuarine beds with their seams of coal und erwent many alternations of circumstances, and that, quick ly as some parts of them were formed, the whole occupied the interval be tween th e Lias and Co rnbra sh,and that th ese marin e san ds are not contemporaneous with the correspondi ng beds in the south, but show us where the fauna went to when it was ousted th ere by newer forms of life, and that th e reason why no Great Oolite is found below the Cornbrash is that the faun a in this case d id not migrate int o Yorkshire, but went to die elsewhere . This is a mere hypothesis, b ut it may serve to help us to get some possible idea as to how th e phenomena might have been brought about. As to the Cornbrash itself, very little is seen of it on the coast. In two places only can it be observed. One of th ese is on th e north side of Scar borough, where it forms a capping to the Upper Estuarin e beds, and gradually crosses the sloping cliff as a con spicuous band, or form erly did so, reaching nearly to the sea-level opposite the Castle. It has a peculiar purplish tinl by which it THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. r3r may anywhere be recognised, and is oolitic. Fossils are numerous in it. The other locality is Gristhorpe Cliff where it behaves in a similar way, being lowest down towards the east. The fossils are often beautiful and very characteristic. '*' Above this are a few feet of inconspicuous clay, with abundance of the characteristic Avicula eel/ina/a. ....;.;....:::: U.C.c."'l1pl'eI'Ca/C-Cn·t .....-:.... M.C.C.=N/ddle .. .•.::,' ..... f,.C.C.='zower" "\ Qu..= FIG. S.-SKETCH GEOLOGICAL MAP OF HACKNESS. r. F. Blake. On entering the Middle Oolite the scene entirely changes. We have had for the most part barren estuarine sandstones to deal with. Now we have calcareous and sandy rocks, many of which are crowded with fossils. But there is a prelude of less interest ing rocks. Undoubtedly the best locality to get a general idea of the whole succession of these rocks is at the remarkable outlier of * The principal are Ammonites macrocephalus. Cardium cognatum. Echinobrissus scutatus. " lunula. Ts-igonia. paucicosta. Terebratula ornithocephala. Chemnitzia -uittata, Goniomya u-scripta; " obovata. Littorina junctura. Modio/a cuneata. Rhynch.onella varians. P leurotomaria guttata. Pectenfibrosus. Myacites recurvus. Oslreaflabelloides. !32 J, F. BLAKE ON THE GEOLOGY OF Hackness. Seen on the geological map ~ this is a perfect picture (Fig. 8). The ;I1 deep valleys are worn down to the 2;; lowest members, which mount one over i: the other on the slopes of the hills w whose summits are crowned with the ~ highest. Yet the beds are not entirely ~ horizontal, but have a gentle dip towards * The principal fossils to be here obtained are- Ammonites convolutus. Belemnites (hlJeni. 1Ifor/iola jndchra. lumtla. A/aria trispill Of the beds that follow, which have been called the" Greystone or Passage beds," very little need be said. The . name is essentially a bad one. When-..., g ever the change of lithology or life is ~ ~ gradual, as it mostly is, there are.3.§ passage beds; these, however, are in ....; no way peculiar, and should be classed with the Lower Limestones. When this is done, we have to say that these limestones, when best de veloped, are Baggy and somewhat im pure below and oolitic above. Each 15.;'j of the three localities where they may =;:; d:l be studied shows special features. The 6 ~ most normal is that at Scarborough ~ :ii Castle, where the beds form the vertical ES ~ rocks which cap the hill. There is no ------doubt of these being good limestones - --- ,--- of about fifty feet in thickness in all. It was natural that these, in the first in- ...; ( stance, should have been taken to be the .;: I Coralline Oolite. Now we know that j, r.;:, j there are two limestones, it is easy to ~ g , --=- cs- __ determine which these belong to ; but .3 ~ I '--"'> _ even without this the difference of the .;:; I __._- fauna should have taught caution. o l There is a very rich and characteristic assemblage in the true Coralline Oolite i FIG. ro.-SECTION ON THE which is lacking here; in its place we NOI<.TH SIDE OF SCAR find abundance of Gervillia aviculoides, BOROUGH CASTLE ROCK. and Echinobrissus scutatus, species -Blake and Hudlcston. always indicative of a low horizon, [Quart. Journ Geol. Soc., vol. with others which are found also xxxiil.] in the Lower Calcareous Grit. In the second locality, at Hack ness itself, a peculiar feature is seen in the interval between the flaggy and oolite portions-a mass of corals. These are of the massive type Thamnastrrea and Isastrcea, or branching Tlzecosmilia and Rhabdophyllia,. they do not, however, appear to be in their place of growth, but to be fragments torn from a reef elsewhere. They are accompanied by numerous shells, mostly of a stunted form and such as usually accompany the corals, and by spines of Cidaris Smithi, to the exclusion of Cid. jlorigemma which is so charac reristic of the upper Rag. At Filey Brig we have some difficulty in matching these rocks. Traced over the whole of the Yorkshire area, we find that the Lower Limestones vary very greatly in thick ness. It would not therefore be surprising if at any locality there should be scarcely any representative of them. On the other ]. F. BLAKE ON THE GEOLOGY OF hand, they may have expanded, or more or less altered in char acter. At the Brig there are fifty feet of beds above the Lower Calcareous Grit, as there are at Scarborough. The lower part of these, lying immediately on the grit with large doggers (called the " Ball" beds), agrees fairly well with the" red beds" at Scarborough, but is richer in fossils. Above this comes a very massive sand stone, ten feet in thickness, and forming a conspicuous feature. Being only seen here it has been called theFiley Brig Calcareous Grit. The question is, does this represent the Middle Calcareous Grit, the x.N .E. 68.0 Foss£l,ferou s "'iley Bri-CJIJ Calc Grit r9.6 - J!' L 'rnestone5 B Impure." ·tiL [ew etnd Gr~ts W~ fossas d25.0 e calctt Beds mol' cl hi hly -reo us, an ':J fossiliferou s. o c::;> ,.,tto.o ~~Q:~_.~"'--- ... l_-- "C... ____ ~. *"#h. <-£0"fffle_, ----rs and- r FIG. IT.-SECTION ACROSS PART OF THE CARR NAZE, FILEY BRIG. W. H. Hudleston. [Proc. Ceol. Assoc' 1 vo1. iv., p. 400.] Lower Limestones having died out or lost their character; or must we look for these Lower Limestones above it? Above it there do come some limestones, of which about twelve or thirteen feet are seen: are these Upper or Lower? The fossil contents seem strongly in favour of the latter, and certainly the Filey Brig Grit is not very like the Middle Calcareous Grit seen elsewhere. As so often is the case, however, both views, so far as the limestones are concerned, may have some truth in them. For when last seen THE COUNTRY BETWEEN REDCAR AND BRIDLIl'\GTON. 137 the Middle Calcareous Grit was dying out, and the two limestones may therefore have come together, and the highest portion represent the Upper Limestones.* There is little or nothing to say about the Middle Calcareous Grit, except that it does not seem to exist in the coast sections at all, and for that reason perhaps has been overlooked; I pass on, therefore, to the Upper Limestones. These also are never seen on the coast (unless the very base occurs at Filey), but always inland, when they are known as Coralline Oolite, chiefly because they are always capped, when un denuded, by a bed of Coral Rag. It is impossible to map this Rag as it is too thin; it is, however, a very distinct deposit. The Coralline Oolite is generally shelly, but occasionally massive, and in this case the apparent absence of fossils is due to their being so imbedded in the matrix that it is im possible to separate them. The Coral Rag is almost made of fossils and their debris. Both of these rocks in their relative positions may be seen on the sides of the Silpho Hill, where there is a quarry. In this quarry the rock is mostly Coralline Oolite filled with the characteristic shells; but at the top and on the fields above are many scattered corals of a massive type. These upper members are better seen to the south along the Forge Valley, which, debouching at Ayton, lands us in a rich hunting ground for fossils of the Coral Rag. t The final term of this Corallian series is the Upper Calcareous Grit. The exposures of this are only in the fields on the summit of the hill; but it is quite characteristic-asmooth honeycombed grit out of which all calcareous matter has been dissolved, containing Pecten midas, AZ1lcula ovalis, var. obli'qua, with Lucina and Pleuromya. Nothing like this is to be found nearer than Picker ing, some twelve miles to the west, but there it may be perfectly matched. Nowhere in the east do we see the relations of the Corallian rocks to the Kimmeridge clay, though the latter is seen overlying the former in the hills above Pickering. Immediately south of Filey Brig there is a fall in the level of the ground, and the entire surface is covered with boulder clay for many miles. It is to be presumed that the great fault which bounds the vale of Pickering on the north is continued out to sea. In this case, not only the * The commonest fossils besides those mentioned above are- Ammonites cordatus, T'rigonia triquetra. Mlllericrinus ectdnatus, Exogyra nana. Lucina Beani. Spongiaflonceps. Pectenfibrosus. R hyncltme/la Th.urnsanni, R haxe/lape>:/Orala (=R. Geroillia aoicidoides. Soroyana), t The following are the commonest fossils in the Coralline Oolite of Hackness- Pseudomeiania striata. Area quadrisulcata. Astarte ovata. Ceritkiu1Jl inornatusn, " pectinala. Exogyra nan-a, Littorina rntcricata; Astarte Duboisiana, Ostrragregaria. Cylindrites Luidii. Some Rag fossils at Ayton are in addition to the above- Nerina-a fusiforniis, Modiola inclnsa, Pseudodiadema versipora. Trochotoma tornata, Limajragilis, Cidaris Smittii. 9 ]. F. BLAKE ON THE GEOLOGY OF Coral Rag and Upper Calcareous Grit will be lost in the interval, but also the lower beds of the Kimmeridge. This, however, is a vast deposit, and it may be nearly horizontal; consequently, when we are four milt's south of Filey we may still he on it. The next certain section, however, is that at Speeton. The Speeton section introduces quite a new set of deposits, and the centre of interest lies in the Cretaceous rocks. Here, beneath the mass of chalk which has risen to the summit of the hills, we find a wild tumbled slope of clay, in which at first sight it is hopeless to make out any order. But with patience it has been done. Occasionally the shore is laid bare by the sea, and then the beds are seen in sequence, though much contorted and dislocated. Moreover, the uniformity of the slopes is broken by ridges, where not so much slipping has taken place, and in these, at times, a section may be seen. Three such ridges divide the area into four parts, which from east to west are Speeton Gap, Black Cliff, Middle Cliff, and New Closes Cliff. Roughly speaking these correspond to the sub-divisions in the series. Those of most undoubted character are the two central ones, the clays of which are of Neocomian age. Prof. Judd thought he could distinguish here the three parts of that series, but Mr. Lamplugh's researches render it doubtful how far this can be relied upon. Mr. Lamp lugh divides the clays by the species of Belemnites, instead of the Ammonites, and states that this is locally the natural sub division. Unfortunately it does not assist very much in the correlation with other areas. The two Belemnites are B. jaculum and B. semicanaliculatus. The major part of the whole section belongs to the former zone and is correlated with the lower Neocomian, and it is in the upper zone alone that we find Am. Deshayesi which is characteristic of Upper Neocomian. There does not seem to be sufficient foundation here for the sub-division of the lower portion of the series into two parts, corresponding to those recognised elsewhere; though Am. noricus is the leading ammonite of the lower part, and Am. speetonensis of the upper. '*' It is about the beds below these that the principal difficulties of correlation arise. At the base is found a remarkable bed of partly phosphatic nodules, which has been called the "Compound nodular bed." This is very rich in fossils, which seem to be a mixture of those occurring above and below, as though there were a break, of which, however, there is no stratigraphical evidence. Below this band is a series of clays and shales, characterised by Belemnites lateralis, which, after about forty feet, terminates down wards in a band of phosphatic nodules called the "Coprolite bed." This series is spoken of by Mr. Lamplugh as the zone of '" The fossils here to be met with are- Ammonites noricus, Exogyra sinuata, Meyeria ornata. " speetonensis. Pecten cinetus. Serpula articulata. Belenenites jacuiunr. lsocardia angulata. Verneicuiaria SO'lueroyi. Rostellaria Phillipsi. R hync1lOnellasutcata, -_.- ~\------_•.=...J:!....!Y._._ _WA E - -_ ! __s« ~. ---!! "_0". \ NARY SPRIN " ~. --' __~4-- ._ __ 0 "'-••'-- . _._. -.- ._.- . -----'- 0 TO''"--- ..-' .., ::r: t'1 o o c:: ...,z ::c -< i:;j .., =;: ~ t'l Z ::c ot'l o :. ::c :>z o to ~ o C z ..,o o ~ -.0"'. Scale 9 inches = 1 mile. 14° ]. F. BLAKE ON THE GEOLOGY OF Belemnites lateralis. Below this again, are soft clays, which Mr. Leckenby reckoned at fifty feet, but which appear to be unnoticed by Mr. Lamplugh; and below these again, thin shales of undoubted Upper Kimmeridgian age, the Lower Portlandian of the French, or as I have called it, Bolonian, Is then the zone of Bel. lateralis Neocomian or Portlandian? Towards answering this question we have the following facts. First, the Coprolite bed at the base contains, in a remanie form, undoubted Portland fossils, particularly Lucina portlandica. Now a remanie fossil signifies that the beds originally containing it have been destroyed, and that the bed now containing it belongs to a new series. That is to say, it is an evidence of unconformity. Secondly, Belemnites lateralis is everywhere reckoned as Neocomian, and there is nothing like it in the Portland. Thirdly, the broad, round-backed ammon ites, if Am. astierianus cannot actually be identified amongst them, at all events belong to a type which is Neocomian and not Portland. Fourthly, the fossil called Am. Gravesianus, which is thought to be Portlandian, on examination by M. Nikitin, turns out to be a Neocomian form. Lastly, it would be very curious indeed if Exogyra sinuata, so characteristic a Neocomian form, should anywhere occur in Portland rocks. These reasons leave no doubt in my own mind, that these beds are Neocornian, and that their reference to Portlandian is founded on error. Never theless, Mr. Lamplugh thinks that they ought to be included in the J urassic series, while M. Pavlov, who is of the same opinion, even correlates them with the true Portland stone, with which, as far as my knowledge goes, they have less than nothing in common. If, however, we correlate the underlying shales with the Upper Kimmeridge, or Bolonian, there should be above them, if anything, some representative of the French Middle Portlandian, or the Portland Sands. I cannot help fancying that the possible fifty feet of clay, which has not been much examined, will be found to belong to this horizon. Perhaps, in spite of his ignorance of there being two" coprolite beds," Prof. Judd's determination of A. gigas and A. giganteus (7) below the coprolite bed may not be altogether wrong, and may refer in part to fossils which lie below both. Passing now to the other end of the section, above the zone of B. jaculum, come some further clays, called the zone of B. semi canaiicuiatus. They are incompletely seen, and appear to be of considerable thickness. They contain in their centre some beds called" cement beds," which have yielded to Prof. Judd a con siderable fauna, but are not now so easily worked. The upper most beds are some black clays. There is little hesitation in including these in the Neocomian as higher beds; but the interesting question is, What is their relation to the clays above, which contain a Gault fauna? There is a nodule bed near, but not at, their base, and they seem to pass conformably into the black Neocomian clays below, and into the Red Chalk above; and why THE COUNTRY BETWEEN REDCAR AND llRIDLINGTON. 141 should they not?* They are, however, extremely interesting, hecause at no other spot north of the Wash can anything but Red Chalk be found above the Neocomian, though something similar may possibly occur at Knapton. This shows that the peculiar limitation of the Yorkshire basin was continued even to the period of the Gault, and that during that period those changes took place which opened up the large basin which extends through Lincoln shire, and contains the Red Chalk continuously. The Red Chalk at Speeton is itself very interesting, for though it is called Red Chalk, it is far more argillaceous here than any where else, and is abnormally thick. The colour, however, in some parts is merely accidental, and has an uneven lower boundary, which crosses the stratification of the beds.r More than one bed of Red Chalk occurs, the upper one belonging to the Chalk itself. Above the lower bed is a very peculiar nodular bed of grey earthy chalk, containing twenty-five per cent. of insoluble matter, with well formed crystals of pyrites, and large specimens of Terebratula biplicata, thus gradually leading us to the usual characteristic beds of the base of the Chalk. Of the Chalk itself little can be said. It is too large a subject to be discussed at the end of a paper dealing with many forma tions, and though the high cliffs of Flamborough are exceedingly beautiful with their bedded flints, and sea-worn caves, they are too inaccessible to give much opportunity of tracing the sub divisions. Suffice it to say, that, after mounting over the lowest beds, all that can be seen belongs to the flinty portion of the series. The flints, however, from two points of view, are worthy of a passing note. In the area between Speeton and Bridlington, spots may be found where the Chalk is very distinctly stratified, but on examining the strata they are found, though white, to scarcely effervesce at all with acid. In other words, the beds in reality consist of flint, or perhaps one should say, silicified chalk. The change isgradual, so that one can scarcely tell where flintbegins and chalk ends. Flints are usually definite segregations of siliceous matter, but here the same substance impregnates a whole bed. The other point is the marvellous variety of sponge flints to be found washed out of the Chalk cliffs, which congregate where the trend of the coast runs south, near Sowerby. The flint has clung round the abundant sponges, and sometimes has filtered into their substance; then we have a definite form of sponge. Sometimes it * The fossils here are- Belemnites 11linimus and vars. Inoceramus sulcatus(f). Nucula jectinata (?). Inoceramus concentricus. Avicula Rawliniana(?). t The fossils obtainable are Versnicaiaria: umbonata. Terebratula semietobosa, Inoceramus sulcatus. llfa){as fund/us. " capil1ata. Ostrea oesiculosa: Rkynclwnella Mantelliana. Terebrafulina striata. Spondylus gibbosus. Tereoratula biplieala. Avicula gryflueoides. Belemnites minintus, 142 THE COUNTRY BETWEEN REDCAR AND BRlDLINGTON. has coated their surfaces, extracted their siliceous matter, and left the sponges as mere dusty hollows in the interior. The upper part of the Chalk is seen on the coast only between Flamborough and Sewerby, but it skirts the western side of the Holderness Plain. Here it is without flints and contains a peculiar fauna, more nearly allied to the fossils of Germany than to those of the south of England. In the more familiar districts we usually speak of the Upper Chalk as Chalk with Flints, though the highest zones are flintless. Here the flintless chalk is so thick and well developed, that we are tempted to call it the Upper Chalk, though belonging to a still higher zone than that which is usually called so. The last deposits we are called upon to notice are the Drifts. These again form a large subject, on which we can scarcely touch. The sea-coast section gives opportunities for study which are denied inland. Mr. Lamplugh, who has studied these beds with care, indicates the existence of two distinct boulder clays, with shelly basement clays below. The section may be well seen between the chalk cliffs and Bridlington, as well as in the infilling of the old preglacial valleys of South Sea Landing, and Dane's Dyke. It is in these basement beds that those remark able masses have been caught up from the sea-bottom, and brought, shells and all, to Bridlington, forming what was once known as the Bridlington Crag. This is not now visible, but a similar mass has been dis covered at South Sea Landing, where it is not likely to be covered up by concrete. The boulders in these beds are also worth a study, and the same may be said of those in the boulder clay, as far as Whitby. Their variety is remarkable; they are only now beginning to be studied with care, and we may expect them to throw light upon the source of the ice which brought them. Boulders should be looked up as the fossils of the period, and collected in the same way, till their origin is traced. Such are the main features of geological interest on the eastern coast of Yorkshire. It will be seen that the merest outline has been given. Nevertheless, so rich, so varied, so marvellous, so unique is the series of sections along the coast, that if we succeed within a week in verifying what is here recorded we shall do well. FIG. 13".-SECTION OF THE CLIFFS BETWEEN BRIDLINGTON QUAY AND SEWERBY.-G. W. Lamp/ugh. [Compte Rendu Congo Ceol. Int., ,888 (,89').l - ---...... _. 1"1'-.1'2 ~ ------'- --_%~~~:~~:_:::--\.. of Horizontal Scale, 12 inches = I mile, ~21B(\. Vertical Scale, 3 times as great, rr\roo I. Fresh-water Marl. 5. Basement Clay or Boulder Clay with shells. za. Fresh-water Gravel. 6. Remanie Chalk. zb. Sewerby Gravel. A. Old Sea-beach of rolled Chalk pebbles. 3a. Upper Purple Boulder Clay. B. Clayey Chalk-wash: an old land surface. 3b. Lower Purple Boulder Clay. C. Clean Blown-sand. 4. Clay, finely stratified, with sand and gravel. X. Ancient cliff of Chalk. 144 ]. F. BLAKE ON THE GEOLOGY OF THE COUNTRY BETWEEN REDCAR AND BRIDLINGTON. NOTE. OF THE ILLUSTRATIONS TO THE ABOVE PAPER, Figs. 10 and 12 are reprinted by permission of the Council of the Geological Society; Figs. 3, 6, 9, and 13 are lent by the Publication Committee of the International Geological Congress; Figs. 5, 7, and II, from early volumes of the Proceedings, are lent by Mr. W. H. Hudleston, F.R.S.: and Figs. I, 2, 4, and 8 have been prepared by the author. [The foregoing paper by Prof. Blake was issued as a separate pamphlet (price sixpence) on July 29th, 1891. It is now reprinted from standing type, with a few unimportant verbal alterations.-ED.]