Records of Woodhall Spa and Neighbourhood Part 5

Geotrupes spiniger Otiorrhyncus picipes

G. stercorarius Psylliodes cupro-nitens

Coccinella 7-punctata Ragonycha fulva

C. variabilis Meligethes aeneus

Strangalia armata Necrophorus humator

Polydrusus pterygomalis N. ruspator

N. mortuorum

Strophosomus coryli Aphodius rufipes

HEMIPTERA-HETEROPTERA

(in Fulsby Wood).

Miris laevigatus Leptopterna ferrugata

Calocoris roseomaculatus torhinus angulatus

Orthotylus scotti

C. bipunctatus Nabis lativentris

(In Tumby Wood.)

Those marked * are new to Lincolnshire.

*Piezodorus lituratus (abundant *Onychumenus decolor on gorse)

Stygnus rusticus (at roots of *Psallus alnicola (on birch) heather)

*Dictyonota strichnocera (on Asciodema obsoletum gorse)

Miris calcaratus Lygus viridis (on birch)

Orthotylus ericetorum (abundant on heather)

SPIDERS.

Anyphaena accentuata Meta segmentata

Epeira gibbosa (a first record) Epeira marmorea (doubtful, not yet recorded in Britain)

Dictyna arundinacea Xysticus pini

Dia dorsata (a first record) Epeira sollers

Epeira quadrata Linyphia triangularis

E. scalaris Theridion varians

CHAPTER VII. GEOLOGICAL NOTES.

In a county like Lincolnshire, mainly agricultural, in which the operations of man are, for the most part, confined to the earth's crust, in ploughing and sowing, and, as some one has said, in "tickling" the earth's surface into fertility,-in such a county we are not led ordinarily to explore the inner bowels of the world; as is necessary in mining districts such as certain parts of Yorkshire, Durham, Cornwall and elsewhere. Yet, with regard to our knowledge of its geological features, Woodhall may be said to compare favourably with a large majority of places. With one exception {84a} it is the spot, _par excellence_, in this part of the kingdom, where the earth's hidden resources have been tapped, and tapped to considerable purpose, in the unique commodity for which it is famed-its mineral water. The book of Nature, so often "sealed," has here been opened and its contents indexed. We have in the strata of the Woodhall well sundry chapters in the earth's past history unfolded, at least to the initiated. The writer is not going to attempt here a systematic disquisition on a subject so abstruse (for which, indeed, he is not qualified), beyond touching upon some of its more salient, or more interesting features. The geological records of the Woodhall well have already been given {84b} in the very concise form in which they have been preserved for us. Whether they are to be entirely depended upon is questionable, but we may here repeat them:-Gravel and boulder clay, 10 feet; Kimeridge and Oxford clays, 350; Kellaways rock, blue clays, cornbrash, limestone, great oolite, clay and limestone, upper Estuarine clay, 140; Lincolnshire oolite, and Northampton sand, 140; lias, upper, middle, and lower, 380 feet; total, 1,120 feet. The mineral spring is said to have issued from a stratum of spongy rock lying at a depth of 540ft. {85a} This would probably be in or near the ferruginous Northampton sand, the lowest layer of the oolite, and lying immediately above the upper lias. {85b}

In the year 1897 a boring was commenced within 500 yards of the original well by the artesian engineers, Messrs. Isler and Co., on behalf of the Rev. J. O. Stephens, on the west side of the Stixwould road, with a view to obtaining a second supply of the Woodhall water; this was carried to a depth of 700 feet. The engineers furnished me with a register of the strata so far pierced by the bore, but, as they are not described in the technical terms of geology, it is rather difficult to compare them with those of the old well. At a depth of 490 feet, sandstone with iron pyrites was pierced; this would probably be the ferruginous Northampton sand of the Oolite. It is at a less depth than the same stratum at the Spa well; but that was to be expected, as geologists state that all the geological strata "dip" eastward, and this bore being to the west, the stratum would naturally tilt upward. This born was ultimately abandoned.

According to the records of the Spa well, derived from Dr. Snaith, of Horncastle, who knew the well from its birth, the saline spring was found at 540ft.; but Dr. Granville, who visited Woodhall, and wrote his version, in 1841, puts it at 510ft. It is difficult to say which of these two doctors, who differ, should be accepted as the more trustworthy; and in 1841 Dr. Granville would still certainly be able to find plenty of persons familiar with the well and its details. But in the ferruginous sand, or near it, the spring was to be expected; and there it would seem Messrs. Isler, in the new boring, found saline water, though only in small quant.i.ty. The depth, according to their computation, was, as we have said 490ft., which is 20ft. above the Spa spring's level, according to Granville's version, and 60ft. above the depth given by Snaith. The paucity of the supply of the saline water in the Isler boring may probably be accounted for thus: The trend of the current found in making the Spa well was said to be from south-east to north-west, whereas this new bore is very nearly due west from the Spa well. If, therefore, the stream is of narrow width, this later boring is scarcely in the position to catch more than the side soakage of the current, and it would seem that the main stream can only be tapped either by another boring further north, or by a lateral shaft from the present bore running northward till it encounters the current. There remains, of course, the further and open question as to whether the saline stream formerly pa.s.sing _through_ the Spa shaft, still continues its former north-westerly course, after having the outlet afforded by that shaft.

Would it not be more in accordance with the law of nature that the stream should take the course of least resistance by rising in the well, and not flowing further along the bed of its special original stratum? If that be so, the only chance of another well would be to bore south-eastward of the Spa; and probably the shaft sunk by the late Mr. Blyton beside Coalpit Wood, if it had been continued, would have proved a safer venture than any other as yet attempted. At some future time we may have the wolf disturbing the stream, above the lamb represented by the original well, to the detriment of the latter. It may be here noticed that in the Scarle boring, as we are told, there was found a strong spring in the upper part of the lower Keuper sandstone at the depth of 790ft., and a still stronger spring at the base of that formation at 950ft. In that case, therefore, as also at Woodhall, the water was found in sandstone, but at a much greater depth, and also in sandstone of a different character, viz., the Keuper at Scarle, the Northampton at Woodhall.

Another difference is that in the Scarle strata we pa.s.s at once from the surface drift to the lower Lias; the Kimeridge clay and all the Oolite formations, which are found at Woodhall, with a thickness of some 630ft., being entirely absent. These differences, of course, ill.u.s.trate the fact that, owing to abrasion and other causes, not only do the strata underlying the surface drift vary in different localities, but their several thicknesses vary; while, as at Harrogate, the mineral properties of the water also vary at a distance of only a few yards. Pa.s.s beyond the limits of the particular stream, and, below ground as well as above it, you are not "in the swim."

In the spring of 1904, Mr. R. A. Came, of the Royal Hotel, commenced sinking a shaft, in search of the Spa water, at a point some mile south of the original well; and early in 1905 water was struck at a depth of 492 feet, which proved to have the same saline properties, with the addition of Epsom salt, a good supply issuing from the spongy sandstone.

This opens up a vista of great possibilities in the future; it does away with the monopoly hitherto existing, and may have a most important effect, in the further development of the Spa. The well is 7ft. in diameter, is bricked to a depth of 495ft., and sunk to 520ft. The boring was carried out by Mr. Joseph Aldridge, of Measham, near Atherstone, Warwickshire, an expert mining engineer. Many fine fossils, as ammonites, belemnites, and bi-valves, were found in the different strata that were pierced.

I now proceed to remark upon some of the geological strata, as found at Woodhall. And first, after the mere surface gravel, we have the Boulder clay. This has a very interesting history. In the "Life of Nansen," the Arctic traveller, it is stated {87a} that the geological strata of the Arctic regions show that at some remote period the climatic conditions were the reverse of those which prevail now. Throughout those regions, at present of intense cold, there was quite a southern climate, in which walnut trees, magnolias, vines, etc., flourished; while, on the other hand, there was also a period during which our own country, and large parts of the Continent, lying in the same lat.i.tude, were buried under vast ice-fields with an Esquimaux climate. It is there further stated {87b} that boulders are found scattered over Norway, Sweden, and Denmark, which have been transported thither on glaciers, from regions still further north. In like manner glaciers at one time also spread over what are now Scotland and a great part of England, bringing along with them boulders from Norway, and Scandinavia generally. The present condition of Greenland, with its vast glaciers, pouring through its valleys, down to the water's edge, on the sea sh.o.r.e, ill.u.s.trates the condition of our own country at that remote period. {88a} As regards this country, these ice-streams may be cla.s.sed under two distinct heads, (_a_) the native, inland glaciers, and (_b_) the north-eastern, Scandinavian glacier. To speak first of the former. As the climate, from causes into which we cannot here enter, {88b} gradually became coldier, glaciers were formed among the rugged hills in the present lake country of c.u.mberland and Westmoreland, some of which pushed their way westward, literally inch by inch, until they debouched in the Irish Sea, and filled it to overflowing, for it is only shallow. From Borrowdale, b.u.t.termere, Eskdale, and other head centres, they also streamed southward and eastward. There was an immense central stream, which forced its way over the wild tract of Stainmoor (named doubtless from the thousands of boulders with which it is strewn); then, fed by lateral branches from many directions, it traversed Teesdale, turned towards the coast, pa.s.sing by Scarborough, and so on to Holderness and the Humber, a branch also filling up Airedale and the Vale of York. {88c} From Holderness it pa.s.sed the Humber, into Lincolnshire. Its most eastern limb would doubtless have debouched in the North Sea, and filled it; but here the north-eastern glacier, to which I have alluded, came into collision.

Taking its rise in Scandinavia, it had spread into a vast sheet in parts 3,000ft. thick, {89a} filled up the shallow North Sea, and the Baltic, a veritable _mer de glace_, and over-run northern Germany, its thickness even at Berlin being supposed to have been 1,300ft. Impinging on our eastern coast of Scotland and of northern England, it spread over a great part of Holderness, meeting and blending with the inland native glacier on the Humber; and the vast united ice-stream thence pursued its onward southern course, enfolding everything in its icy embrace, to the Thames and to the Severn. {89b} These great ice-streams created the geological formation called "The Drift," or boulder-clay, which we have at Woodhall.

The clay is simply the _detritus_, produced by the grinding, through long ages, of the rocks under the vast and weighty ice-fields slowly moving over them, and the abrasion of the hill-sides which they sc.r.a.ped in their course. The boulders are detached fragments, which fell from various rocky heights overhanging the ice-stream, rested on the surface of the ice-sheet, were borne along by it through hundreds of miles, and when, in the course of ages untold, the climate became milder, and the glaciers gradually shrunk and eventually disappeared, these fragments, often bearing the marks of ice-sc.r.a.ping, and oftener rounded by ice-action, fell to the soil beneath, and remain to this day, to bear their silent witness to the course once taken by the giant ice-stream. The period through which this process was going on has been variously computed, from 18,000 years, according to the estimate of Major-General A. W. Drayson, F.R.A.S., who gives elaborate astronomical statistics in support of his views (Trans. Victoria Inst.i.tute, No. 104, p. 260), to 160,000, as calculated by Mr. James Croll ("Climate and Time"). It is now generally held that there were more than one ice-age, with inter-glacial breaks.

These boulders are abundant in our neighbourhood, and of all sizes. They may be measured by inches or by yards. There is a good-sized one in the vicarage garden at Woodhall Spa, which the present writer had carted from Kirkby-lane, a distance of a mile and a half. There is a larger one lying on the moor, near the south-east corner of the Ostler Ground. The writer has one in his own garden, a large one, more than 6ft. in length by 3ft. high, and 2ft. thick. It took five horses to drag it from its position, a quarter of a mile distant. There are six visible in the parish of Langton, two or three large ones near Old Woodhall Church; several large ones in Thimbleby, Edlington, and elsewhere. Smaller ones are often to be seen placed at turns in the roads to prevent drivers running their vehicles into the bank, or used as foundations to old cottages or farm buildings; and still smaller specimens may be constantly picked up by the pedestrian, or the sportsman, in his rambles through the fields. Much interest has of late years been taken in these boulders, arising from the distinct cla.s.ses of glaciers to which I have referred, and the consequent difference between the nature of the boulders, as well as the source from which they have come, according as they belong to the one cla.s.s or the other; and our Lincolnshire Naturalists' Union have now a special "boulder committee" engaged in the investigation of this subject.

The late Professor Sedgewick, of Cambridge (whose lectures the writer attended), was the first to notice that along the Holderness sh.o.r.e there were (as he says) "an incredible number of blocks of granite, gneiss, greenstone, mica, etc., etc., resembling specimens derived from various parts of Scandinavia." {90} These, we now know, were dropped by the great Scandinavian glacier; and, along with the kinds of stone here named, there are also boulders of Rhombporphyry (the "Rhomben porphyry"

of Norwegian geologists, from the neighbourhood of Christiana), Augite syenite, and several more, not of British origin. These boulders are now being searched for, and found in our own neighbourhood. On the other hand, there is the different cla.s.s of boulders which were brought down by the native inland glaciers. These consist largely of igneous kinds. The rugged hills of the Lake district owe their origin to fire; and the boulders which the glaciers have transported correspond. The shap granite, for instance, which is probably one of the commonest of this cla.s.s, comes from the shap granite bed of Wastdale, in c.u.mberland.

Boulders of this rock, as Mr. Kendall tells us, "pa.s.sed over Stainmoor in tens of thousands," {91a} to visit us in Yorkshire and Lincolnshire.

Other kinds are Felspar porphyry from Eskdale, in c.u.mberland, Andesite from Borrowdale, Granophyr from Ennerdale and b.u.t.termere, Quartz, Basalt, and several more from the crystalline formations in the Lake district.

Several boulders of these rocks have also been found in our own neighbourhood; and doubtless more remain to reward the explorer. {91b} I have dwelt at some length on this particular formation-the boulder clay-because it is the most ready to hand; it lies on the surface, in many parts around us, within the ken of the ordinary visitor to Woodhall Spa. It may give an additional interest to his rambles in search of health, to know that he may, at any moment, pick up a boulder which has travelled further, and pa.s.sed through more strange vicissitudes, than he can well have done himself; perhaps, with Shakespeare, to read "Sermons in Stones," and to moralise on the brevity of human life, with all its ailments, compared with those ages untold, through which the pebble in his hand slowly {91c} travelled on its long, laborious journey, to rest at length as a const.i.tuent element of the locality, where he himself is seeking relief and recreation.

To the west of Woodhall Spa, beyond the Stixwould-road, near the vicarage, and northward, the surface sand, in some parts, at the depth of a foot, or slightly more, hardens into an ironstone, so compact that tree roots cannot penetrate it. In root-pruning or manuring apple-trees, I have found the tap-root stunted into a large round k.n.o.b, further downward growth being prevented by this indurated formation. This oxide of iron also pervades the sandy soil, in parts, to a depth of four or five feet, impregnating the water with ferruginous properties, so that it "ferrs"

bottles, or vessels, in which it is allowed to stand for any length of time. In consequence, the water frequently has a dull appearance, although the iron may probably make it a wholesome tonic.

The surface sand, which is of a still lighter character on the moor ground in Woodhall, and in Martin, Roughton, and Kirkby, contiguous to Woodhall, is what is technically called the "Old Blown Sand," borne by the winds from the whilom salt marshflats of the Witham, when it was much wider than at present, and a tidal arm of the sea. It is comparatively a recent formation, yet abounding in fine particles, or pebbles, of quartz, and other elements of far earlier date; the larger of these are often rounded by tidal action. Below this surface sand we find, in many parts, a blue clay of varying depth. In a pit called Jordan's pond, in an abandoned brickyard on the east of the road to Stixwould, it is at least 16ft. thick; also, in a large pit in Kirkstead, near Hogwood, some half-mile south-east of the Abbey Inn, which was dug to procure this clay, for "claying" the light super-soil, otherwise almost barren, it is many feet thick. Ammonites and other fossils are plentiful in it, often cemented together with veins of gypsum. Both these pits are mentioned in the Government Geological Survey (pp. 152, 153) of "The country around Lincoln." Close by the latter pit the writer once found a curious fossil, which was for some time a puzzle to all who saw it. It is now in the British Museum, and was p.r.o.nounced to be an Echinus crashed into an Ammonite.

The Kimeridge clay, named as the next stratum in the bore of the Woodhall well, crops up first about Halstead Hall in Stixwould, and continues through Woodhall to Horncastle, and so on to Wragby and Market Rasen. It abounds in fossils. Mr. Skertchly {92} found in the first of the pits just named, that this clay was divided into three layers, the upper being a line of Septaria (or nodules) full of serpulae one foot in depth, then soft dark-blue clay, 6ft.; and below that another course of Septaria; and Professor J. R. Blake records from this pit the following fossils{93a}:-Belemnites nitidus, Ammonites serratus, Rissoa mosensis, Avicula aediligensis, Cyprina cyreneformis, Ostrea deltoides, Lima aedilignensis, Thracia depressa, Arca, Serpula tetragona. In other pits in the neighbourhood several other fossils have been found. {93b} [For a list of fossils found about Woodhall see Appendix II.] A peculiarity of this stratum is that the upper part of it contains bands of "inflammable shales," being blue, laminated, bituminous clays, which burn readily. It was the presence of these which has tempted explorers to throw away their money in search of coal; as in the case at Donington on-Bain, where Mr.

Bogg drove a bore to the depth of 309ft., but only found clay and thin bands of inflammable schist. {93c} In the case of Woodhall Spa, the money thrown away on one purpose has brought health and wealth to others, from a source then undreamt of in man's philosophy. We cannot leave the Kimeridge clay without noting that its presence at Woodhall, in the position where it is, as the _first_ geological formation below the surface drift, opens to us a vista-reveals to us a yawning _hiatus_-which embraces a vast expanse of time.

In the normal order of geological strata, the whole series of cretaceous formations have to be pa.s.sed through before reaching the Oolite formation, of which the Kimeridge clay forms almost the upper layer. But at Woodhall and the surrounding district the whole of this series of rocks and soils is wanting. Their absence is eloquent, and tells a tale of widespread destruction. Standing near the Tower on the Moor we can see in the distance, stretching from north-west to south east, the range of hills called the "Wolds," which, with a "cap" of marls, or sandy and flinty loams, are composed almost entirely of chalk; from them, near c.a.w.kwell Hill (the hill _par excellence_ of chalk), comes the water supply of Horncastle and Woodhall. They extend for a length of some 45 miles, with a width of some six miles to eight. The actual depth of the chalk is not exactly known, but a boring made through it, near Hull, reached the Oolite beneath at 530ft. We may perhaps, therefore, put the average at 500ft. {94a} Doubtless, at one period, this cretaceous formation extended over the whole tract of country, but southward and westward from the foot of the present wolds it has since been swept away.

And this must have taken place before the glacial period, because the glacial boulder clay lies upon the Kimeridge clay, which normally underlies the chalk. Mr. Jukes Brown ("Geological Journal," No. 162, p.