56 THE PrkBECK BEDS OP THE VALE OF WAEDOr/R. [Feb. 1 894. 



taken in 1890, is shown in the diagram of 1881 as 12 inches 

 thick : in reality it thickens from 1 to 12 inches westward in a 

 distance of 30 yards, and it is this bed in its expanded form which 

 is touched at the top of the quarry at Lower Chicksgrove, and which 

 is seen to he nearly 3 feet thick in the quarry on Lady Down (p. 54). 

 On the other hand, the overlying white fissile limestone thickens 

 from west to east, being only 4 inches thick on Lady Down and at least 

 16 inches in the railway-cutting. The lower white limestone seems to 

 be a local bed which thins out in both directions. The diagram 

 (fig. 2, on the opposite page) shows the variations in the strata 

 between the two well-marked horizons of the ' Cinder-bed ' and the 

 ArcJiceoniscus-limestone at the two localities mentioned, and at a 

 third one still farther east. 



We now come to the most easterly exposures near Dinton Station, 

 where the eastward dip brings in still higher beds and ultimately 

 those which we believe to be of Upper Purbeck age. The cutting 

 which runs through a wood, and commences about 700 yards west 

 of Dinton Station, has been quarried back for stone and exposes the 

 same part of the series as that seen in the middle of the larger 

 cutting to the west, but several of the beds have thinned out, so 

 that the space between the ' Cinder-bed ' and the topmost sands is 

 greatly contracted. The lower part of this section from the Archceo- 

 niscus-heA downward is given in fig. 2 ; above that horizon the 

 following beds are seen in the eastern corner of the old quarry : — 



Feet. Inches. 



Sticky grey clay, seen for 6 



Brownish clay, passing down into whitish marly clay with irregular 



lumps of hard shelly limestone at intervals 1 



Layer of fibrous carbonate of lime (' beef ) up to 2 



Layers of grey shaly clay, sandy shale, and yellow sand, with 



crushed shells 2 6 



Lenticules of sandy limestone and ' beef in brownish sandy 



shale 6 



Hard, buff-coloured, sandy limestone, solid in the upper part, 



laminated in the lower part 1 



Brown sandy shale and clay, with crushed shells 8 



Hard, crystalline, shelly limestone 1^ 



Compact, grey, marly limestone {Arckaoniscus-hed) with many 



specimens of Arch<eo?iiscus 4 



6 n 



These beds dip south-eastward and appear to pass below a thick 

 bed of clay which is now grassed over, but seems to be about 8 feet 

 thick ; this is overlain by soft yellow sand with a thin surface- 

 covering of gravel, the two together often slipping over the claj\ 

 The cutting then ends, and the ground falls to a little watercourse, 

 which passes under the railway about 400 yards west of the 

 station. 



We take this clay and sand to be the basement-beds of the Upper 

 Purbeck group, but we are by no means sure that they are in direct 

 succession to the beds above described. If the section just given be 



