to remain at all times in perfect shelter and security. A copious and transparent spring bursts out from a cavern just below the village, and after turning a mill, flows into the bay. The rock from which the water issues, is composed of sharp fragments of flint imbedded in chalk rubble, cemented together by stalactitical deposition. LIGN. 33.-PLAN OF THE STRATA ON THE WEST SIDE OF LULWORTH COVE. 1. Chalk. 4. Wealden. 2. Firestone. 5. Purbeck. 3. Galt. The cliffs around this semicircular basin present the same section as those in Worbarrow; the entire series of strata, from the chalk to the oolite, being clearly exposed. The plan, lign. 33, explains the relative position of the deposits, as seen on the west side of the bay. On the east side, a similar section occurs, as represented in lign. 34; and the chalk, firestone, galt, Wealden, Purbeck, and Portland beds, are seen in their natural order of superposition, in a distance of between five and six hundred yards, proceeding from north to south. A view of this part of the bay, from the west, is given, Pl. XVII. In this sketch a small portion of the base of the chalk downs is visible on the left; the low cliffs that succeed and wind round the middle of the bay, are the lower cretaceous strata, and the clays and sands of the Wealden. The headland at the entrance of the cove, consists of contorted Purbeck beds, resting on the Portland oolite, of which large masses project on the shore. The appearance of the undulated layers of Purbeck limestone is very striking in the weathered portions of the cliff, from the intermediate clays having been worn away, and the bands of stone left prominent. The blocks on the right, in the foreground, are of Purbeck limestone, and extend towards those that form the opposite bar. Wealden Purbeck Portland LIGN. 34.-SECTION OF THE EAST SIDE OF LULWORTH COVE. (Dr. Fitton.) Firestone Gal Dr. Fitton, with characteristic accuracy and minuteness of detail, has given measurements of the spaces occupied by the different groups of strata below the chalk in Lulworth Cove. The firestone and galt are about 150 feet; the Wealden beds, 600 feet; the Purbeck, 450 feet; and the Portland, 240 feet. The fossils here met with are lignite, and a few paludinæ and uniones, in the Wealden; and in the Purbeck, shells of the same genera occur in layers, and mussel-shells abundantly in a coarse green sandrock, as at Durlstone Head. FOSSIL TREES.-Seams of lignite are numerous in the Wealden sands and clays, as in Swanage Bay, and in Brook Bay, in the Isle of Wight. In the Portland strata, a little way to the eastward, are petrified trees, still attached to the soil in which they grew. These were first observed by the present Dean of Westminster, and Sir H. De la Beche.* The sketch in lign. 35, copied from the "Memoir on the Chalk * "Geological Transactions," vol. iv. Geology of Weymouth," by these distinguished geologists, illustrates the position of the strata and fossil trees. LIGN. 35. SECTION EXPOSED IN THE CLIFF EAST OF LULWORTH COVE. b, b. The "dirt-bed," with fossil trees. (From the Geological Transactions.) On doubling the rocks on the east corner of the cove, the Purbeck beds are seen resting on the oolite, and forming South Cliff, which is surrounded by the insulated masses of rock that appear on the west side of Worbarrow Bay. (See Pl. XVI., p. 268.) It is about a furlong to the east of Lulworth Cove, in the highly inclined strata of the cliff, that a considerable number of' petrified trunks of trees are exposed. Some are entirely laid bare by the washing of the sea, and others partly so; but several are almost wholly encased by concretions of soft burr-stone, and have their roots fixed in a layer of black earth (termed "dirt-bed" by the quarrymen); in precisely the same relative position, and interspersed with similar rounded fragments of limestone, as in the fossil forest of the Isle of Portland, hereafter noticed. The lowermost strata are the Portland oolitic limestones, full of marine shells; on them is superimposed the layer termed the "dirt-bed," with the fossil trees. This is R |