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Part 10

Science in Arcady · Grant Allen — chapter 10 of 16 · ~5,792 words · public domain

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This is a general law, indeed, that runs through all nature, from London slums to the deep sea. Wasteful species produce many young, and take but little care of them when once produced. Economical species produce very few young, but start each individual well-equipped for its place in life and look after them closely till they can take care of themselves in the struggle for existence. And on the average, however many or however few the offspring to start with, just enough attain maturity in the long run to replace their parents in the next generation. Were it otherwise, the sea would soon become one solid mass of herring, cod, and mackerel.

These cat-fish, however, are not the only good fathers that carry their young (like woodcock) in their own mouths. A freshwater species of the Sea of Galilee, Chromis Andreae by name (dedicated by science to the memory of that fisherman apostle, St. Andrew, who must often have netted them), has the same habit of hatching out its young in its own gullet: and here again it is the male fish upon whom this apparently maternal duty devolves, just as it is the male cassowary that sits upon the eggs of his unnatural mate, and the male emu that tends the nest, while the hen bird looks on superciliously and contents herself with exercising a general friendly supervision of the nursery department. I may add parenthetically that in most fish families the eggs are fertilised after they have been laid, instead of before, which no doubt accounts for the seeming anomaly.

Still, good mothers too may be found among fish, though far from frequently. One of the Guiana catfishes, known as Aspredo, very much resembles her countrywoman the Surinam toad in her nursery arrangements. Of course you know the Surinam toad--whom not to know argues yourself unknown--that curious creature that carries her eggs in little pits on her back, where the young hatch out and pass through their tadpole stage in a slimy fluid, emerging at last from the cells of this living honeycomb only when they have attained the full amphibian honours of four-legged maturity. Well, Aspredo among cat-fish manages her brood in much the same fashion; only she carries her eggs beneath her body instead of on her back like her amphibious rival. When spawning time approaches, and Aspredo's fancy lightly turns to thoughts of love, the lower side of her trunk begins to assume, by anticipation, a soft and spongy texture, honeycombed with pits, between which are arranged little spiky protuberances. After laying her eggs, the mother lies flat upon them on the river bottom, and presses them into the spongy skin, where they remain safely attached until they hatch out and begin to manage for themselves in life. It is curious that the only two creatures on earth which have hit out independently this original mode of providing for their offspring should both be citizens of Guiana, where the rivers and marshes must probably harbour some special danger to be thus avoided, not found in equal intensity in other fresh waters.

A prettily marked fish of the Indian Ocean, allied, though not very closely, to the pipe fishes, has also the distinction of handing over the young to the care of the mother instead of the father. Its name is Solenostoma (I regret that no more popular title exists), and it has a pouch, formed in this case by a pair of long broad fins, within which the eggs are attached by interlacing threads that push out from the body. Probably in this instance nutriment is actually provided through these threads for the use of the embryo, in which case we must regard the mechanism as very closely analogous indeed to that which obtains among mammals.

Some few fish, indeed, are truly viviparous; among them certain blennies and carps, in which the eggs hatch out entirely within the body of the mother. One of the most interesting of these divergent types is the common Californian and Mexican silver-fish, an inhabitant of the bays and inlets of sub-tropical America. Its chief peculiarity and title to fame lies in the extreme bigness of its young at birth. The full-grown fish runs to about ten inches in length, fisherman's scale, while the fry measure as much as three inches apiece; so that they lie, as Professor Seeley somewhat forcibly expresses it, 'packed in the body of the parent as close as herrings in a barrel.' This strange habit of retaining the eggs till after they have hatched out is not peculiar to fish among egg-laying animals, for the common little brown English lizard is similarly viviparous, though most of its relatives elsewhere deposit their eggs to be hatched by the heat of the sun in earth or sandbanks.

Mr. Hannibal Chollop, if I recollect aright, once shot an imprudent stranger for remarking in print that the ancient Athenians, that inferior race, had got ahead in their time of the modern Loco-foco ticket. But several kinds of fish have undoubtedly got ahead in this respect of the common reptilian ticket; for instead of leaving about their eggs anywhere on the loose to take care of themselves, they build a regular nest, like birds, and sit upon their eggs till the fry emerge from them. All the sticklebacks, for instance, are confirmed nest-builders: but here once more it is the male, not the female, who weaves the materials together and takes care of the eggs during their period of incubation. The receptacle itself is made of fibres of water-weeds or stalks of grass, and is open at both ends to let a current pass through. As soon as the lordly little polygamist has built it, he coaxes and allures his chosen mates into the entrance, one by one, to lay their eggs; and then when the nest is full, he mounts guard over them bravely, fanning them with his fins, and so keeping up a continual supply of oxygen which is necessary for the proper development of the embryo within. It takes a month's sitting before the young hatch out, and even after they appear, this excellent father (little Turk though he be, and savage warrior for the stocking of his harem) goes out attended by all his brood whenever he sallies forth for a morning constitutional in search of caddis-worms, which shows that there may be more good than we imagine, after all, in the domestic institutions even of people who don't agree with us.

The bullheads or miller's thumbs, those quaint big-headed beasts which divide with the sticklebacks the polite attentions of ingenious British youth, are also nest-builders, and the male fish are said to anxiously watch and protect their offspring during their undisciplined nonage. Equally domestic are the habits of those queer shapeless creatures, the marine lump-suckers, which fasten themselves on to rocks, like limpets, by their strange sucking disks, and defy all the efforts of enemy or fishermen to dislodge them by main force from their well-chosen position. The pretty little tropical walking-fish of the filuroid tribe--those fish out of water--carry the nest-making instinct a point further, for they go ashore boldly at the beginning of the rainy season in their native woods, and scoop out a hole in the beach as a place of safety, in which they make regular nests of leaves and other terrestrial materials to hold their eggs. Then father and mother take turns-about at looking after the hatching, and defend the spawn with great zeal and courage against all intruders.

I regret to say, however, there are other unprincipled fish which display their affection and care for their young in far more questionable and unpleasant manners. For instance, there is that uncanny creature that inserts its parasitic fry as a tiny egg inside the unsuspecting shells of mussels and cockles. Our fishermen are only too well acquainted, again, with one unpleasant marine lamprey, the hag or borer, so called because it lives parasitically upon other fishes, whose bodies it enters, and then slowly eats them up from within outward, till nothing at all is left of them but skin, scales, and skeleton. They are repulsive eel-shaped creatures, blind, soft, and slimy; their mouth consists of a hideous rasping sucker; and they pour out from the glands on their sides a copious mucus, which makes them as disagreeable to handle as they are unsightly to look at. Mackerel and cod are the hag's principal victims; but often the fisherman draws up a hag-eaten haddock on the end of his line, of which not a wrack remains but the hollow shell or bare outer simulacrum. As many as twenty of these disgusting parasites have sometimes been found within the body of a single cod-fish.

Yet see how carefully nature provides nevertheless for the due reproduction of even her most loathsome and revolting creations. The hag not only lays a small number of comparatively large and well-stored eggs, but also arranges for their success in life by supplying each with a bundle of threads at either end, every such thread terminating at last in a triple hook, like those with which we are so familiar in the case of adhesive fruits and seeds, like burrs or cleavers. By means of these barbed processes, the eggs attach themselves to living fishes; and the young borer, as soon as he emerges from his horny covering, makes his way at once into the body of his unconscious host, whom he proceeds by slow degrees to devour alive with relentless industry, from the intestines outward. This beautiful provision of nature enables the infant hag to start in life at once in very snug quarters upon a ready-made fish preserve. I understand, however, that cod-fish philosophers, actuated by purely personal and selfish conceptions of utility, refuse to admit the beauty or beneficence of this most satisfactory arrangement for the borer species.

Probably the best known of all fishes' eggs, however (with the solitary exception of the sturgeon's, commonly observed between brown bread and butter, under the name of caviare), are the queer leathery purse-shaped ova of the sharks, rays, skates, and dog-fishes. Everybody has picked them up on the seashore, where children know them as devil's purses and devil's wheelbarrows. Most of these queer eggs are oblong and quadrangular, with the four corners produced into a sort of handles or streamers, often ending in long tendrils, and useful for attaching them to corallines or seaweeds on the bed of the ocean. But it is worth noticing that in colour the egg-cases closely resemble the common wrack to which they are oftenest fastened; and as they wave up and down in the water with the dark mass around them, they must be almost indistinguishable from the wrack itself by the keenest-sighted of their enemies. This protective resemblance, coupled with the toughness and slipperiness of their leathery envelope or egg-shell, renders them almost perfectly secure from all evil-minded intruders. As a consequence, the dog-fish lay but very few eggs each season, and those few, large and well provided with nutriment for their spotted offspring. It is these purses, and those of the thornback and the edible skate, that we oftenest pick up on the English coast. The larger oceanic sharks are mostly viviparous.

In some few cases, indeed, among the shark and ray family, the mechanism for protection goes a step or two further than in these simple kinds. That well-known frequenter of Australian harbours, the Port Jackson shark, lays a pear-shaped egg, with a sort of spiral staircase of leathery ridges winding round it outside, Chinese pagoda wise, so that even if you bite it (I speak in the person of a predaceous fish) it eludes your teeth, and goes dodging off screw-fashion into the water beyond. There's no getting at this evasive body anywhere; when you think you have it, it wriggles away sideways, and refuses to give any hold for jaws or palate. In fact, a more slippery or guileful egg was never yet devised by nature's unconscious ingenuity. Then, again, the Antarctic chimaera (so called from its very unprepossessing personal appearance) relies rather upon pure deception than upon mechanical means for the security of its eggs. The shell or case in this instance is prolonged at the edge into a kind of broad wing on either side, so that it exactly resembles one of the large flat leaves of the Antarctic fucus in whose midst it lurks. It forms the high-water mark, I fancy, of protective resemblance amongst eggs, for not only is the margin leaf-like in shape, but it is even gracefully waved and fringed with floating hairs, as is the fashion with the expanded fronds of so many among the gigantic far-southern sea-weeds.

A most curious and interesting set of phenomena are those which often occur when a group of fishes, once marine, take by practice to inhabiting freshwater rivers; or, vice-versa, when a freshwater kind, moved by an aspiration for more expansive surroundings, takes up its residence in the sea as a naturalised marine. Whenever such a change of address happens, it usually follows that the young fry cannot stand the conditions of the new home to which their ancestors were unaccustomed--we all know the ingrained conservatism of children--and so the parents are obliged once a year to undertake a pilgrimage to their original dwelling-place for the breeding season.

Extreme cases of terrestrial animals, once aquatic in habits, throw a flood of lurid light (as the newspapers say) upon the reason why this should be so. For example, frogs and toads develop from tadpoles, which in all essentials are true gill-breathing fish. It is, therefore, obvious that they cannot lay their eggs on dry land, where the tadpoles would be unable to find anything to breathe; so that even the driest and most tree-haunting toads must needs repair to the water once a year to deposit their spawn in its native surroundings. Once more, crabs pass their earlier larval stages as free-swimming crustaceans, somewhat shrimp-like in appearance, and as agile as fleas: it is only by gradual metamorphosis that they acquire their legs and claws and heavy pedestrian habits. Now there are certain kinds of crab, like the West Indian land-crabs (those dainty morsels whose image every epicure who has visited the Antilles still enshrines with regret in a warm corner of his heart), which have taken in adult life to walking bodily on shore, and visiting the summits of the highest mountains, like the fish of Deucalion's deluge in Horace. But once a year, as the land-crabs bask in the sun on St. Catherine's Peak or the Fern Walk, a strange instinctive longing comes over them automatically to return for a while to their native element; and, obedient to that inner monitor of their race, down they march in thousands, velut agmine facto, to lay their eggs at their leisure in Port Royal harbour. On the way, the negroes catch them, all full of rich coral, waiting to be spawned; and Chloe or Dinah, serves them up hot, with breadcrumbs, in their own red shells, neatly nestling between the folds of a nice white napkin. The rest run away, and deposit their eggs in the sea, where the young hatch out, and pass their larval stage once more as free and active little swimming crustaceans.

Well, crabs, I need hardly explain in this age of enlightenment, are not fish; but their actions help to throw a side-light on the migratory instinct in salmon, eels, and so many other true fish which have changed with time their aboriginal habits. The salmon himself, for instance, is by descent a trout, and in the parr stage he is even now almost indistinguishable from many kinds of river-trout that never migrate seaward at all. But at some remote period, the ancestors of the true salmon took to going down to the great deep in search of food, and being large and active fish, found much more to eat in the salt water than ever they had discovered in their native streams. So they settled permanently in their new home, as far as their own lives went at least; though they found the tender young could not stand the brine that did no harm to the tougher constitutions of the elders. No doubt the change was made gradually, a bit at a time, through the brackish water, the species getting further and further seaward down bays and estuaries with successive generations, but always returning to spawn in its native river, as all well-behaved salmon do to the present moment. At last, the habit hardened into an organic instinct, and nowadays the young salmon hatch out like their fathers as parr in fresh water, then go to the sea in the grilse stage and grow enormously, and finally return as full-grown salmon to spawn and breed in their particular birthplace.

Exactly the opposite fate has happened to the eels. The salmonoids as a family are freshwater fish, and by far the greater number of kinds--trout, char, whitefish, grayling, pollan, vendace, gwyniad, and so forth--are inhabitants of lakes, steams, ponds, and rivers, only a very small number having taken permanently or temporarily to a marine residence. But the eels, as a family, are a saltwater group, most of their allies, like the congers and muraenas, being exclusively confined to the sea, and only a very small number of aberrant types having ever taken to invading inland waters. If the life-history of the salmon, however, has given rise to as much controversy as the Mar peerage, the life-history of the eel is a complete mystery. To begin with, nobody has ever so much as distinguished between male and female eels; except microscopically, eels have never been seen in the act of spawning, nor observed anywhere with mature eggs. The ova themselves are wholly unknown: the mode of their production is a dead secret. All we know is this: that eels never reproduce in fresh water; that a certain number of adults descend the rivers to the sea, irregularly, during the winter months; and that some of these must presumably spawn with the utmost circumspection in brackish water or in the deep sea, for in the course of the summer myriads of young eels, commonly called grigs, and proverbial for their merriment, ascend the rivers in enormous bodies, and enter every smaller or larger tributary.

If we know little about the paternity and maternity of eels, we know a great deal about their childhood and youth, or, to speak more eelishly, their grigginess and elverhood. The young grigs, when they do make their appearance, leave us in no doubt at all about their presence or their reality. They wriggle up weirs, walls, and floodgates; they force there way bodily through chinks and apertures; they find out every drain, pipe, or conduit in a given plane rectilinear figure; and when all other spots have been fully occupied, they take to dry land, like veritable snakes, and cut straight across country for the nearest lake, pond, or ornamental waters.

These swarms or migrations are known to farmers as eel-fairs; but the word ought more properly to be written eel-fares, as the eels then fare or travel up the streams to their permanent quarters. A great many eels, however, never migrate seaward at all, and never seem to attain to years of sexual maturity. They merely bury themselves under stones in winter, and live and die as celibates in their inland retreats. So very terrestrial do they become, indeed, that eels have been taken with rats or field-mice undigested in their stomachs.

The sturgeon is another more or less migratory fish, originally (like the salmon) of freshwater habits, but now partially marine, which ascends its parent stream for spawning during the summer season. Incredible quantities are caught for caviare in the great Russian rivers. At one point on the Volga, a hundred thousand people collect in spring for the fishery, and work by relays, day and night continuously, as long as the sturgeons are going up stream. On some of the tributaries, when fishing is intermitted for a single day, the sturgeons have been known to completely fill a river 360 feet wide, so that the backs of the uppermost fish were pushed out of the water. (I take this statement, not from the 'Arabian Nights,' as the scoffer might imagine, but from that most respectable authority, Professor Seeley.) Still, in spite of the enormous quantity killed, there is no danger of any falling off in the supply for the future, for every fish lays from two to three million eggs, each of which, as caviare eaters well know, is quite big enough to be distinctly seen with the naked eye in the finished product. The best caviare is simply bottled exactly as found, with the addition merely of a little salt. No man of taste can pretend to like the nasty sun-dried sort, in which the individual eggs are reduced to a kind of black pulp, and pressed hard with the feet into doubtful barrels.

In conclusion, let me add one word of warning as to certain popular errors about the young fry of sundry well-known species. Nothing is more common than to hear it asserted that sprats are only immature herring. This is a complete mistake. Believe it not. Sprats are a very distinct species of the herring genus, and they never grow much bigger than when they appear, broches, at table. The largest adult sprat measures only six inches, while full-grown herring may attain as much as fifteen. Moreover, herring have teeth on the palate, always wanting in sprats, by which means the species may be readily distinguished at all ages. When in doubt, therefore, do not play trumps, but examine the palate. On the other hand, whitebait, long supposed to be a distinct species, has now been proved by Dr. Guenther, the greatest of ichthyologists, to consist chiefly of the fry or young of herring. To complete our discomfiture, the same eminent authority has also shown that the pilchard and the sardine, which we thought so unlike, are one and the same fish, called by different names according as he is caught off the Cornish coast or in Breton, Portuguese, or Mediterranean waters. Such aliases are by no means uncommon among his class. To say the plain truth, fish are the most variable and ill-defined of animals; they differ so much in different habitats, so many hybrids occur between them, and varieties merge so readily by imperceptible stages into one another, that only an expert can decide in doubtful cases--and every expert carefully reverses the last man's opinion. Let us at least be thankful that whitebait by any other name would eat as nice; that science has not a single whisper to breathe against their connection with lemon; and that whether they are really the young of Clupea harengus or not, the supply at Billingsgate shows no symptom of falling short of the demand.

AN ENGLISH SHIRE.

For the reasons which have determined the existence of Sussex as a county of England, and which have given it the exact boundaries that it now possesses, we must go back to the remote geological history of the secondary ages. Its limits and its very existence as a separate shire were predetermined for it by the shape and consistence of the mud or sand which gathered at the bottom of the great Wealden lake, or filled up the hollows of the old inland cretaceous sea. Paradoxical as it sounds to say so, the Celtic kingdom of the Regni, the South Saxon principality of AElle the Bretwalda, the modern English county of Sussex, have all had their destinies moulded by the geological conformation of the rock upon which they repose. Where human annals see only the handicraft and interaction of human beings--Euskarian and Aryan, Celt and Roman, Englishman and Norman--a closer scrutiny of history may perhaps see the working of still deeper elements--chalk and clay, volcanic upheaval and glacial denudation, barren upland and forest-clad plain. The value and importance of these underlying facts in the comprehension of history has, I believe, been very generally overlooked; and I propose accordingly here to take the single county of Sussex in detail, in order to show that when the geological and geographical factors of the problem are given, all the rest follows as a matter of course. By such detailed treatment alone can one hope to establish the truth of the general principle that human history is at bottom a result of geographical conditions, acting upon the fundamentally identical constitution of man.

In a certain sense, it is quite clear that human life depends mainly upon soil and conformation, to an extent that nobody denies. You cannot have a dense population in Sahara; and you can hardly fail to have one in the fruitful valley of the Nile. The growth of towns in one district rather than another must be governed largely by the existence of rivers or harbours, of coal or metals, of agricultural lowlands or defensible heights. Glasgow could not spring up in inland Leicestershire, nor Manchester in coalless Norfolk. Insular England must naturally be the greatest shipping country in Europe; while no large foreign trade is possible in any Bohemia except Shakespeare's. So much everybody admits. But it seems to me that these underlying causes have coloured the entire local history of every district to an extent which few people adequately recognise, and that until such recognition becomes more general, our views of history must necessarily be very narrow. We must see not only that something depends upon geographical configuration, not even merely that a great deal depends upon it, but that everything depends upon it. We must unlearn our purely human history, and learn a history of interaction between nature and man instead.

From the great central boss of the chalk system in Salisbury Plain, two long cretaceous horns or projections run out to eastward towards the Channel and the German Sea. These two horns, separated by the deep valley of the Weald, are known as the North and South Downs respectively. The first great spur or ridge passes through the heart of Surrey, and then forms the backbone of Kent, expanding into a fan at its eastward extremity, where it topples over abruptly into the sea in the sheer bluffs which sweep round in a huge arc from the North Foreland in the Isle of Thanet, to Shakespeare's Cliff at Dover. The second or southernmost range, that of the South Downs, parts company from the main boss in Hampshire, and runs eastward in a narrower but bolder line, till the Channel cuts short its progress in the water-worn precipice of Beachy Head. Between these two ranges of Downs lies the low forest region of the Weald, and between the South Downs and the sea stretches a long but very narrow strip of lowland, beginning at Chichester, and ending where the chalk cliffs first meet the shore beside the new Aquarium and Chain Pier at Brighton. Thus the whole of Sussex consists of three well-marked parallel belts: the low coast-line on the south-west, the high chalk Downs in the centre, and the Weald district on the north and north-west. As these three belts determine the whole history and very existence of Sussex as an English shire, I shall make no apology for treating their origin here in some rapid detail.

The oldest geological formation with which we have to deal in Sussex (to any considerable extent) is the Wealden: so that our inquiry need not go any farther back in the history of the world than the later secondary ages. Before that time, and for long aeons afterward, the portion of the earth's crust which now forms Sussex had probably never emerged from the ocean. Britain was then wholly represented by the primary regions of Wales, Scotland, and Cornwall, forming a small archipelago or group of rocky islands separated at some distance by a wide passage from the nucleus of the young European continent. But by the Wealden period, the English Channel and the Eastern half of England had been considerably elevated above the level of the sea. Great rivers and lakes existed in this new continental region, much like those which now exist in Sweden, Northern Russia, and Canada; and the deposits of sand or mud formed at their bottoms or in their estuaries compose the chief part of the Wealden formation in England. Without going fully into this question (somewhat complicated by frequent changes of level), it will suffice for our present purpose to say that the Wealden consists, in the main, of two great divisions, which form, so to speak, the floor, or lowest story, of the Sussex formations. The first or bottom division is chiefly composed of a rather soft and friable sandstone, which runs through the whole Forest Ridges, and crops out in the grey cliffs of Hastings and Fairlight. The second or upper division is chiefly composed of a thick greasy clay, which forms the soil in the greater part of the Weald, and glides unobtrusively under the sea in the flat shore on either side of Hastings, giving rise to the lowlands of Pevensey Bay and the Romney Marshes. Why the sandstone, which is really the bottom layer, should appear higher than the clay in these places, we shall see a little later.

After the deposition of the gritty or muddy Wealden beds in the lake and embouchure of the old continental river, there came a second period of considerable depression, during which the whole of south-eastern England was once more covered by a shallow sea. This sea ran, like an early northern Mediterranean, right across the face of Central Europe; and on its bottom was deposited the soft ooze of globigerina shells and siliceous sponge skeletons which has now hardened into chalk and flint. A great cretaceous sheet thus overlay the Wealden beds and the whole face of Sussex to a depth of at least 600 feet; and if it had not been afterwards worn off in places, as the nursery rhyme says of old Pillicock, it would be there still. I need hardly say that the chalk is yet en evidence along the whole range of South Downs, and forms the tall white cliffs between Brighton and Beachy Head.

Finally, during the Tertiary period, another layer of London clay and other soft deposits was spread over the top of the chalk, certainly on the strip between the South Downs and the sea, and probably over the whole district between the Channel and the Thames valley: though in this case, later denudation has proceeded so far that very few traces of the Tertiary formations are preserved anywhere except in the greater hollows.

Such being the original disposition of the strata which compose Sussex, we have next to ask, What are the causes which have produced its existing configuration? If the whole mass had merely been uplifted straight out of the sea, we ought now to find the whole country a flat and level table-land, covered over its entire surface with a uniform coat of Tertiary deposits. On digging or boring below these, we ought to come upon the chalk, and below the chalk again, with its cretaceous congeners the greensand or the gault, we ought to meet the Weald clay and the Hastings sand. Wherever a seaward cliff exhibited a section for our observation, we ought to find these same strata all exposed in regular order--the sandstone at the bottom, the clay above it, the broad belt of chalk halfway up, and the Tertiary muds and rubbles at the top. But in the county as we actually find it, we get a very different state of things. Here, the surface at sea-level is composed of London clay; there, a great mound of chalk rises into a swelling down; and yonder, once more, a steep escarpment leads us down into a broad lowland of the Weald. The causes which have led to this arrangement of surface and conformation must now be considered with necessary brevity.

The North and South Downs, with all the country between them, form part of a great fold or outward bulge of the strata above enumerated, having its centre about the middle line of the Forest Ridge. Imagine these strata bent or pushed upward by an internal upheaving force acting along that line, and you will get a rough picture of the original circumstances which have led to the existing arrangement of the county. You would then have, instead of a flat table-land, as supposed above, a great curved mountain slope, with its centre on top of the Forest Ridge. This gentle slope would rise from the sea between Chichester and a point south of Beachy, would swell slowly upward till it reached a height of two or three thousand feet at the Surrey border, and would fall again gradually towards the Thames valley at London. On the southern side of the Downs this is pretty much what we now get, the Tertiary strata being preserved in the district near Chichester; though farther east, around Newhaven and Beachy Head, the sea has encroached upon the chalk so as to cut out the great white cliffs which bound the view everywhere along the shore from Brighton to Eastbourne. In the central portion of the boss, however, almost all the highest elevated part has been denuded by ice or water action. Between the North and South Downs, where we ought to find the mountain ridge, we find instead the valley of the Weald. Here the chalk has been quite worn away, giving rise to the steep escarpment on the northern side of the South Downs, seen from the Devil's Dyke, so that at the foot of the sudden descent we get the Weald clay exposed; while in the very centre of the upheaved tract the clay itself has been cut through, and the Hastings sand appears upon the surface. Moreover, the sand, being upraised by the central force, stands higher than the clay on either side, which forms the trough of the Weald; and thus the forest ridge, which abuts upon the sea in the cliffs of Hastings Castle, seems to lie above the clay, under which, however, it really glides on either side. I need hardly add that this rough diagrammatic description is only meant as a general indication of the facts, and that it considerably simplifies the real geological changes probably involved in the sculpture of Sussex. Nevertheless, I believe it pretty accurately represents the main formative points in the ante-human history of the county.

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