34 PROCEEDINGS COTTESWOLD CLUB 191 2 



to give the Members an opportunity of becoming acquainted with western 

 Dorset, and more particularly with the coast line between Charmouth and 

 Portland. He said there was a great variety of rocks in the district they were 

 to investigate, and in places they were very much faulted. For this and other 

 reasons it was difficult to describe in a few words the precise origin of the 

 varied scenery around them. The main point, however, is that the Upper 

 Greensand transgresses from east to west the basset edges of successively 

 older deposits. Thus at Thorncombe Beacon to the east of Seatown it rests 

 upon the Upper Lias Sands, or as they are called in this neighbourhood, the 

 Bridport Sands ; but at the flat-topped Golden Cap on the west, on the 

 Middle Lias. 



Chidcock Quarry Hill is capped with Inferior Oolite, but here and there 

 are masses of Fullers' Earth, which have been preserved by having been let 

 down by faulting. Quarrying operations have been very extensive in the 

 past, but now only one quarry is in work. 



The first section examined was that in which the Fullers' Earth is seen. 

 At its base was observed " The Scroff," a rich brown and purplish clayey marl, 

 4 to 6 inches thick, resting upon the Zigzag-Bfd, which is a rubbly bluish, 

 ironstained limestone, full of ammonites (CEcotfausles cf. serrigerus Waagen, 

 etc), Cnllyrites ovalis, Terebratula slephani, etc., on an average 3 inches thick. 

 Below come limestones of schloenbachi date — the rock for which the quarry 

 was opened. 



Mr S. S. Buckman did not detect " The Scroff," or Zigzag-'Bvd here 

 nor the layer of Irtiellci date.* As he remarks, the limestone of this date 

 at Burton Bradstock contains abundantly a small variety of Terebratula 

 spheroidalis." In one of the old workings near the onlj' cjuarry now in work 

 on the hill, however, pieces of limestone full of such small cxam])les of this 

 Terebratula were seen, and if — as seems probable — they indicate a depo.sit of 

 truellei date the sequence of the " Top-Beds " here comes into line with that 

 at Barton Bradstock. 



The second section examined was that in the only quarry now in work 

 on the hill. 



In it, at the top, is rubble of the basement-bed of the " Top-Beds " 

 Below it come the " Red-Beds," The top foot is more of a limestone, is 

 grey and not rich brown and ironshot like the remainder of the deposit. 

 The " Red Beds " are joined on to the rock of mitrchisoufB date, which is 

 one foot thick. 



Descending the wheel-track, the Members saw at a level only a lew feet 

 below that of the floor of the quarry, an exposure of the Bridport Sands, here 

 rich in specimens of Rhynclionella peutaptycta, S. Buckman, V ariamussiiim 

 ItBviradiatus (Waagen) and Serpttla. 



Thus here between the Upper Lias Sands and the limestone that is equi- 

 valent to the C/v/>ei«5-Grit of the Cotteswolds there are only a few feet of 

 rock — a very diifferent n\atter to the great thickness of strata as seen at 

 Leclchampton Hill. From the hill the Members proceeded to Seatown on 

 the coast. 



The heat did not stimulate the party to walk along the shingle to the 

 place below the Down Cliffs, where blocks of the curious " transition-bed " 

 at the junction of the Middle and Upper Lias occur. Instead, they spent the 

 time leisurely, each one according to his own inclinations. The botanists were 

 active, however, but both Chidcock Quarry Hill and the coast near Seatown, 

 were singularly unproductive of rare plants, though a bit of the beautiful 

 vetchling, Lathyrus sylveslris, was seen at the road side, and some Alexanders 

 near Seatown. There was, however, a real interest in tracing the poverty 



I. Quart. Journ. Geol. Soc, vol. Ixvi. (igjo p. 57. 3. Idem., p. 73. 



