weAlden beds. 9 



conspicuously. In the uppermost blue beds the sojidstones, 

 except close to the base, are not prominent ; in the lower they 

 form a marked feature. The thickness, moreover, of the lower 

 set reaches 222 feet, that of the upper only about 92 feet, 

 while, lastly, fosiils occur abundantly close to the base of the 

 lower set of blue shales, but have not been found in the 27 feet 

 of the upper set which are clearly exposed. The evidence is 

 therefore rather more in favour of there being two horizons in the 

 Wealden series of Compton Bay, at which fossiliferous shales occur. 

 Which of the two sets of shales should be compared with the 

 Wealden Shales of Shepherd's Chine remains doubtful. If 

 we correlate the lower set with the shales of Shepherd's Chine, 

 we have nothing to represent the upper 285 feet of Wealden 

 Beds of Compton Bay. But no evidence can be found of so 

 great an erosion of the Wealden Beds as the absence of the strata 

 in question would seem to imply. We may more probably view 

 the lower shales of Compton Bay as a local intercalation of 

 this Wealden type among the variegated beds. 



Before leaving Compton Bay we will refer briefly to the 

 section of the Wealden Beds at Punfield, on the coast of 

 Dorsetshire, already referred to. The Wealden Shales at that 

 locality form a well-marked subdivision at the top of the Wealden 

 group. They have a total thickness of 34^ feet, cypridiferous 

 paper-shales, hard limestone with Ci/rena and Paludina, and some 

 thin bands of sandstone being interstratified with them. Down- 

 wards they pass into white sandstone, grey clays with white sands 

 or brown sandstone, and so into red marls. About 200 feet below 

 them lie white clays and sands, with much lignite and con- 

 cretionary lumps containing JJnio valdensis. The total thickness 

 of the variegated beds of the Wealden, near Punfield, has been 

 estimated by various observers at 1,500 to 2,000 feet. 



Descending Section of the Wealden Beds from Compton Bay to 

 Brooh Point. {See Plates II. and III.) 



Ft. In. 



Perna Bed (Compton Bay). 



f Beds seen only in land-slips, consisting of Cyprid shales witli 



I a hard band, containing numerous fish-remains in the 



g* I upper part, bands of limestone and ironstone ; estimated at 



"S Blue and grey clay and sand . - - . . 



02 I Sand ---.... 



c <( Blue shale ------- 



a White sand and grit ---.-, 



Ochry band (cinder-bed) passing into a solid ironstone where 



less weathered ---... 



Blue shale -----.. 



Cinder-bed, as above ----». 



Grey clay, with large trunks of trees - - . 



Purple marls ----.-. 



"White sandstone and clay with lignite - « . 



Pur})le marls with sand-beds, about - - - . 



Fine white sand ■-..., 



Pale purple clay -.-... 



