256 A. J. Jukes-Browne — The Purheck Beds 



learnt that they contain plenty of Cypridea punctata without any 

 C. granulosa. 



In 1890 this cutting was partially grassed over, and the relations 

 of the beds seen in it to those in the next cutting were not clear. 

 The publication of our account induced Mr, Woodward to visit the 

 place again, and he was fortunate enough to find that the cutting 

 bad been freshly widened so that the succession could be clearly 

 seen; further, by digging below the level of the rails, he carried 

 his measurements down to the Archceonisciis bed. Some of these 

 beds were admitted by Mr. Woodward to be of Upper Purbeck age, 

 but the greater part of what we had regarded as Upper Purbeck 

 was referred by him to the Wealden. 



With respect to the beds seen in the cutting, I accept the fresh 

 evidence obtained by him : I agree with him as to the plane of 

 division between the Middle and Upper Purbeck groups, and admit 

 that there is no necessity for the hypothetical faults which we had 

 introduced. I have no reason to doubt his measurements of the 

 beds in the middle of the anticline, but think that the sand and 

 clay at the base of the Upper Purbecks must thicken to the west- 

 ward. Some of the sand which I saw at the eastern end of the 

 second cutting may have been rearranged, but I do not think there 

 was less than 6- feet of it in situ, or less than 4 feet of the clay 

 below. This view is confirmed by the section in the deep cutting 

 south of Teffont (not described by Mr. Woodward) ; we gave 

 a complete account of the beds therein exposed, and it is now quite 

 clear that they include the base of the Upper Purbeck. The highest 

 beds seen are as follows : — 



ft. in. 

 Wet grey and yellow sand ... ... . .-. 3 or 4 



Light-grey sticky clay 18 



Soft marly clays with thin brown iron -stained layers ... 2 

 Light buff -coloured marl ... ... ... ... ... 4 



Hard whitish grey-hearted sUty limestone 1 



The limestone is clearly the same as that taken at the top of the 

 Middle Purbeck in the Dinton cutting, and there is here 4 feet of 

 marl and clay above it, succeeded by more than that thickness of 

 sand. Mr. Andrews and I also saw the same limestone in the next 

 cutting (south-east of Chicksgrove Farm), overlain by grey and 

 yellow clay, brown sand and sandstone, and a gravelly soil, but 

 these upper beds were confused by slipping ; they are clearly 

 a remnant of the outlier of Upper Purbeck subsequently mapped 

 by Mr. Eeid north-west of the Farm. 



The basal part of the Upper Purbeck group being now established, 

 there remains the question of its upper limit, and this we admit to 

 be difficult of settlement. Mr. Woodward draws the line between 

 Purbeck and Wealden, quite arbitrarily, at a thin layer of sand seen 

 in the cutting about 10 feet below the surface of the ground. Of 

 the beds thus referred to the Wealden Mr. Eeid remarks, "In the 

 Dinton cutting only some ten feet of the lower part of the Wealden 

 Beds can be examined, and the exact age of these deposits is perhaps 

 not quite satisfactorily made out." He thus admits that their age 



