TRANSACTIONS OP SECTION C. 191 



Bed from tlie top of the cliff to below the beach. The junction with the Port- 

 land Stone is not well shown in Durlston Bay. 



The cliffs near Kimmeridge give a continuous section from the lowest Purbeck 

 (on the top of St. Alban's Head) to a low horizon in the Kimmeridge Clay, more 

 than 1000 feet of strata in all. From the head westwards they show a descending 

 section in gently inclined strata, and at rather more than 500 feet below the 

 top of the Kimmeridge Clay the 'Kimmeridge coal,' or ' brownstone,' emerges 

 from below the beach. This highly bituminous layer is about 2 feet 10 inches 

 thick, and has been worked in the neighbourhood from time immemorial, firstly 

 for the manufacture of ornaments or utensils, latterly as a fuel and as a source 

 of oil. During the war it attracted much attention as a possible source of oil 

 and other products. Alum was also once manufactured here. In Hobarrow Bay 

 the main anticlinal axis is reached, and thence westwards the same strata are 

 crossed in ascending order, until the beetling crag formed by the Portland Stone 

 comes down to the beach and stops further progress. 



Lulworth Cove illustrates the effect of attacks by the surf upon nearly vertical 

 strata, varying in their power of resistance. The Portland Stone has formed 

 a natural break-water, which, however, has been breached in places. Stair 

 Hole shows the first effects of a breach ; the waves have worn holes through the 

 .stone, and are swilling the debris of the soft Upper Purbeck and Wealden strata 

 through them. In Lulworth Cove the breakwater has been completely broken 

 through, and a beautifully symmetrical natural harbour formed in the outcrops 

 of the Purbeck, Wealden, and Gault formations. Everywhere the sea suffers 

 a prolonged check on reaching the chalk. 



The east side of Lulworth Cove shows all the formations below the chalk 

 except the Lower Greensand, but much attenuated as compared with Swanage. 

 Here an imconformity below the Gault, which becomes most pronounced at 

 White Nothe, a few miles westwards, becomes manifest for the first time. The 

 absence of Lower Greensand may be due in part to overstep by the Gault, 

 and some of the uppermost Wealden beds also may be absent for the same 

 reason. The section at White Nothe shows the Gault resting on steeply up- 

 turned Wealden, Purbeck, and Kimmeridge strata, and proves that there has 

 been produced in pre-Gault times a set of flexures wholly independent of those 

 of post-Oligocene age, though parallel to them. These earlier flexiu'es are 

 ignored by the rivers. 



Mupe Bay, east of Lulworth Cove, affords a clear view of the passage of 

 the Purbeck beds up into the Wealden, and of the abrupt but conformable junc- 

 tion of the Lower Purbeck and Portland Stone. Half a mile east of Lulworth 

 Cove a ledge of the cliff provides an luirivalled opportunity of examining the 

 lower part of the Purbeck beds, including the junction with the Portland Stone, 

 the thin layer of carbonaceous, gravelly soil known as the dirt-bed, numerous 

 stumps and prostrate trunks of coniferous trees silicified and enclosed in cal- 

 careous tufa, and the brecciated limestones associated with tufa, known as the 

 ' bix)ken beds.' Here the incoming of bands of tufa, among the sedimentary 

 limestones, and the close association of such incoming with brecciation of the 

 limestones, can be studied in detail. Westward from Lulworth Cove the cliffs 

 illustrate the intense compression and supplementary overthrusting which all 

 the formations have undergone in the neighboairhood of the Isle of Purbeck 

 Fault. 



2. The Chinefi of Botirnpninulh. By Henry Bury, F.G.S. 



The country round Bournemouth consists of an almost level plateau, intersected 

 by numerous valleys, and some of the latter, running down to the sea, are of a 

 precipitous character, and are distinguished under the name of ' Chines.' They 

 are usually described as having started as small gullies in the face of the cliff 

 and having worked back inland ; but the evidence seems to be against this. 

 Not only is there no sign of special activity at their heads, but each is found to 

 consist nf an older valley with a U-shaped section, and a newer one. shorter and 

 narrower, shaped like a V. The older valleys probably joined the Frome-Solent 

 River about 1-2 miles from the present shore-line ; the newer ones owe their 



