On Bio-Geology : Part 4

Health and Education
by Rev. Charles Kingsley

(Page 11 of 20)

Now hence arise questions which may puzzle the mind of a Hampshire naturalist. You have in this neighbourhood, as you well know, two, or rather three, soils, each carrying its peculiar vegetation. First, you have the clay lying on the chalk, and carrying vast woodlands, seemingly primeval. Next, you have the chalk, with its peculiar, delicate, and often fragrant crop of lime-loving plants; and next you have the poor sands and clays of the New Forest basin, saturated with iron, and therefore carrying a moorland or peat-loving vegetation, in many respects quite different from the others. And this moorland soil, and this vegetation, with a few singular exceptions, repeats itself, as I daresay you know, in the north of the county, in the Bagshot basin, as it is called - the moors of Aldershot, Hartford Bridge, and Windsor Forest.

Now what a variety of interesting questions are opened up by these simple facts. How did these three floras get each to its present place? Where did each come from? How did it get past or through the other, till each set of plants, after long internecine competition, settled itself down in the sheet of land most congenial to it?

And when did each come hither? Which is the oldest? Will any one tell me whether the heathy flora of the moors, or the thymy flora of the chalk downs, were the earlier inhabitants of these isles? To these questions I cannot get any answer; and they cannot be answered without first - a very careful study of the range of each species of plant on the continent of Europe; and next, without careful study of those stupendous changes in the shape of this island which have taken place at a very late geological epoch. The composition of the flora of our moorlands is as yet to me an utter puzzle. We have Lycopodiums - three species - enormously ancient forms which have survived the age of ice: but did they crawl downward hither from the northern mountains, or upward hither from the Pyrenees? We have the beautiful bog asphodel again - an enormously ancient form; for it is, strange to say, common to North America and to Northern Europe, but does not enter Asia - almost an unique instance. It must, surely, have come from the north; and points - as do many species of plants and animals - to the time when North Europe and North America were joined. We have, sparingly, in North Hampshire, though, strangely, not on the Bagshot moors, the Common or Northern Butterwort (Pinguicula vulgaris); and also, in the south, the New Forest part of the county, the delicate little Pinguicula lusitanica, the only species now found in Devon and Cornwall, marking the New Forest as the extreme eastern limit of the Atlantic flora. We have again the heaths, which, as I have just said, are found neither in America nor in Asia, and must, I believe, have come from some south-western land long since submerged beneath the sea. But more, we have in the New Forest two plants which are members of the South Europe, or properly, the Atlantic flora; which must have come from the south and south-east; and which are found in no other spots in these islands.

I mean the lovely Gladiolus, which grows abundantly under the ferns near Lyndhurst, certainly wild but it does not approach England elsewhere nearer than the Loire and the Rhine; and next, that delicate orchid, the Spiranthes æstivalis, which is known only in a bog near Lyndhurst and in the Channel Islands, while on the Continent it extends from southern Europe all through France. Now, what do these two plants mark? They give us a point in botany, though not in time, to determine when the south of England was parted from the opposite shores of France; and whenever that was, it was just after the Gladiolus and Spiranthes got hither. Two little colonies of these lovely flowers arrived just before their retreat was cut off. They found the country already occupied with other plants; and, not being reinforced by fresh colonists from the south, have not been able to spread farther north than Lyndhurst. Thus, in the New Forest, and, I may say, in the Bagshot moors, you find plants which you do not expect, and do not find plants which you do expect; and you are, or ought to be, puzzled, and I hope also interested, and stirred up to find out more.

I spoke just now of the time when England was joined to France, as bearing on Hampshire botany. It bears no less on Hampshire zoology. In insects, for instance, the presence of the purple emperor and the white admiral in our Hampshire woods, as well as the abundance of the great stag-beetle, point to a time when the two countries were joined, at least, as far west as Hampshire; while the absence of these insects farther to the westward shows that the countries, if ever joined, were already parted; and that those insects have not yet had time to spread westward. The presence of these two butterflies, and partly of the stag-beetle, along the south-east coast of England as far as the primeval forests of South Lincolnshire, points - as do a hundred other facts - to a time when the Straits of Dover either did not exist, or were the bed of a river running from the west; and when, as I told you just now, all the rivers which now run into the German Ocean, from the Humber on the west to the Elbe on the east, discharged themselves into the sea between Scotland and Norway, after wandering through a vast lowland, covered with countless herds of mammoth, rhinoceros, gigantic ox, and other mammals now extinct; while the birds, as far as we know; the insects; the fresh-water fish; and even, as my friend Mr. Brady has proved, the Entomostraca of the rivers, were the same in what is now Holland as in what is now our Eastern counties. I could dwell long on this matter. I could talk long about how certain species of Lepidoptera - moths and butterflies - like

Papilio Machaon and P. Podalirius, swarm through France, reach up to the British Channel, and have not crossed it; with the exception of one colony of Machaon in the Cambridgeshire fens. I could talk long about a similar phenomenon in the case of our migratory and singing birds: how many exquisite species - notably those two glorious songsters, the Orphean Warbler and Hippolais, which delight our ears everywhere on the other side of the Channel - follow our nightingales, blackcaps, and warblers northward every spring almost to the Straits of Dover: but dare not cross, simply because they have been, as it were, created since the gulf was opened, and have never learnt from their parents how to fly over it.

W. Isbister & CO., 1874.
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