206 EEV. J. F, BLAKE ON THE 



mud below or became agglutinated to the basal sands when a and c 

 had died out. 



This passes up into (e) a bed which below is a calc-tuff, but which 

 gradually changes through a fine-grained broken -shell limestone 

 into a fine white unfossiliferous limestone, and continues in an 

 irregular manner into (/) a rather thick-bedded limestone. These 

 three have a maximum united thickness of about 12 feet. They die 

 out one after another against the basal sands, whose upper part has 

 hereabouts a more continuous hardened block. The termination of/ 

 is not seen ; but the end of the others may be traced in the interval 

 between the two quarries. In the next quarry to the south, how- 

 ever, the top block of the basal sands has again 6 inches of stone 

 full of Cerithium portlandicum surmounting it, showing that d is 

 discontinuous by erosion and not by lack of deposit. The beds thus 

 enumerated are nowhere else seen in the quarries ; but the Purbecks 

 which overlie the basal sands on the western side may all be iden- 

 tified with those that are to follow. The first of these {g, fig. 3) is a 

 light limestone brash, 6 feet in thickness where first seen, but rapidly 

 diminishing to zero. Incorporated in it are various stones derived 

 from the three lower beds, containing, of course, the fossils of the 

 beds from which they are derived ; but there are sandy masses as 

 well, so as to leave no doubt of the remaniS nature of the stones ; 

 towards the top this bed becomes more compact. Purther on in the 

 same quarry-face are two shallow erosions such as might be made by 

 a winding river ; and they are half filled by deposits similar to g, 

 dying out on their sides. These are darker-coloured at the base, 

 and contain very obvious stones. The compact upper portion (h) is 

 continuous into the first hollow, and is then cut ofi", but occurs 

 again in the next hollow ; it attains a maximum of 2 feet, when it 

 becomes quite a creamy limestone and yields small Paludince. 

 Above this comes (^) a dark line of earth which becomes black 

 towards the east, and contains many little white stones, as if it were 

 a " dirt bed " or vegetable mould. This passes into (Jc) a limestone 

 brash, which yielded me a crocodilian scute. These two beds com- 

 mence at one end of the quarry at 1 foot, increasing to 4 feet, and 

 then die away to 21 feet. Above comes (7) some thin-bedded ferru- 

 ginous-looking stone, which gradually thickens : the base is still 

 more ferruginous and solid ; but I have not seen any fossils in it. 

 The topmost deposit (m) beneath what may be an overwash of any 

 age, though distinct from the modern soil, is another dark earthy 

 band similar to i or the base of g. All these numerous beds die out 

 shortly to the south, though the manner of their disappearance is 

 not visible ; for in the next quarry (fig. 4) we find nothing but the 

 flaggy beds of the first, N.E., pit overlying the basal sands. 



Having thus followed the several beds along the eastern side, we 

 are able to understand better the appearance presented l^y the western 

 face of the greater quarries (figs. 5-7). None of the deposits from 

 a to / can be recognized ; but the basal sands present an undulating 

 surface, on which lies a brownish calcareous earth with stones of 

 various sizes along the bottom, and attaining a maximum of 3 



