long line of coast running in a N.E. and S.W. direction across this island, (the lower oolitic group.) Eastward of this coast and separated from it by a deep deposit of mud, was formed, at a later period, a long parallel range of coral reef, (the Oxford clay and Coral rag). These coralline ranges were, probably, for some time sinking below the level at which the insects formed them (as is believed to be the case at present with the coral reefs of the Pacific,) and were in part covered by another vast thickness of clayey sediment (the Kimmeridge clay,) and by other calcareous strata (the Portland beds;) after which a new elevation of this area must have occurred, bringing up the surface above the sea-level, so as to give rise to the formation of the Purbeck beds in fresh or brackish water. Another depression must have then taken place, during which the sands of the lower Cretaceous group accumulated, and which, probably, reached its maximum in the period when the thick mass of white chalk was slowly and quietly settling at the bottom of a 'deep deep sea.' Then this district rose again so near the sea-level as to receive the littoral gravel, clays, and sands of the lower and middle Eocene groups. And the rise seems to have continued until these marine beds, with the chalk on which they rest, not only became dry land, but reached the elevation at which we now find them of 1000 feet above the sea.

That all these several changes occupied periods of immense duration, is proved not merely by the enormous thickness of the various beds thus heaped one over the other, but still more by the changes of animal life which accompanied their deposition—thousands of species having become extinct one by one, and succeeded by other thousands as gradually brought into being;-those found in the more recent or highest beds becoming by degrees more and more like those which are now in existence, until some few at first, and afterwards a large proportion, appear identical with them. By what secondary causes the changes in animal life were brought about, remains (and will probably always remain,) a mystery. The same may be said, perhaps, of the contemporary changes of superficial level. Both processes were, undoubtedly, gradual and continuous through countless ages. And during all that time not

a vestige of Man was impressed upon any portion of the earth's surface. We are apt to pride ourselves on the possession in our county of the remains of some of the earliest human inhabitants of the island. But long before the first aboriginal 'ran wild' in our 'woods,' all the changes I have rehearsed had ceased, the surface of the country had assumed its present form-its chalk hills, and their outlying patches of tertiary sands and gravels stood at their present high levels; its valleys had been excavated, and covered by land floods with more recent gravels of terrestrial origin filled with bones of elephant, hippopotamus, and other animals now foreign to England, and its surface occupied by the races of the vegetable and animal creation now existing here. These, be it remembered, are not imaginary speculations, but facts, attested by evidence quite as strong as that which proves the early occupation of our hills by the unknown builders of Stonehenge, Abury, and the races whose remains fill our barrows. The strata that compose those hills and the vales at their foot, are, indeed, the mausolea of countless generations of the ancient living inhabitants of this area of the world's surface. But they are chiefly of marine origin, and testify to the predominance of the ocean over dry land in this district throughout the earliest ages to which its geological structure carries us back. Thus is seen to arise the alliance between two of the subjects with which our Society occupies itself. Geology takes up the history of our district at the point where the local annals of its human inhabitants are obscured by the mists of antiquity, and carries it backward through infinite cycles of ages to an equally misty beginning, by the light of Palæontological' evidence disentombed from the bowels of the earth. No one can assert that this branch of our studies has not its own special attraction to every inquiring mind. I hope that the rude sketch here offered of its chief points, may recommend it to the attention of some who have not yet become alive to the interest it is fitted to command.

114

The Flora of Wiltshire,

COMPRISING THE

Flowering Plants and Ferns indigenous to the County;

By THOMAS BRUGES FLOWER, M.R.C.S., F.L.S., &c., &c.
No. II.

PHYSICAL GEOGRAPHY.

ILTSHIRE one of the south-western counties of England,

is bounded north-west, and north by Gloucestershire; northeast by Berkshire; south-east by Hampshire; south-west by Dorsetshire, and west by Somersetshire. The form or outline of the county is nearly that of a quadrangle, having its angles respectively, near Lechlade, Sopworth, west of Malmesbury; Stourhead, west of Mere; and Cadnam, on the verge of the New Forest. Its utmost length from north to south is almost 54 miles, and its extreme breadth east and west, nearly 37 miles. The area is estimated at 1352 square miles, and it lies between the parallels 50° 55° and 51° 43° north latitude, 1° 29° and 2o 21° west longitude.

The surface of the county is varied and undulating throughout. It includes lofty hills, spacious valleys, extensive irrigated cornfields (both upland and plain), and open downs, presenting very bold and commanding views. On a general survey, Wiltshire will be found to present as great a variety of scenery as any inland county in the kingdom. In some parts the naked downs impart a wildness to the prospect, which is strikingly contrasted with the numberless beauties scattered over the face of the county by the hand of art: while the hills, aspiring to the bold character and picturesque

From a recent survey, the greatest dimension or length of the county, measured north and south, is from the border of Gloucestershire, between Cirencester and Fairford, to the border of Dorsetshire near South Damerham, between Cranbourne in Dorsetshire and Fordingbridge in Hampshire. The greatest breadth from east to west is from the junction of the three counties of Hampshire, Berkshire, and Wiltshire at Inkpen Beacon, to the border of Somersetshire at Midford Bridge, south of Bath.