110 MESSRS. A. J. JUKES-BROWNE AND W. HILL : [May 1 896, 



But, with the exception of a rare specimen of Ammonites ManteUi, 

 the Chalk Marl cephalopoda do not descend below the base of the 

 Chalk. 



The section at Whitenose appears to be similar to that at Lul- 

 worth, but thence westward there is no cliff-section of Cretaceous 

 rocks for a long distance. Inland exposures as far west as Brid- 

 port show a sequence like that of Lulworth ; the Lower Chalk is as 

 thick or thicker, and has the same fossiliferous nodule-bed at the 

 base. 



Between this district and Pinhay, near Lyme Regis, a distance 

 of about 14 miles, the whole of the Chalk has been removed by 

 Tertiary erosion, but sections of the Gault and Greensand show 

 that this lower stage attained a thickness of nearly 200 feet in the 

 extreme east of Dorset, 



3. Devon. 



"We now come to Devon, where the Greensand attains a great 

 thickness, and the representative of the Lower Chalk differs as 

 much from the ordinary English type as that does from the French 

 Cenomanian. We have seen that in West Dorset the Lower Chalk 

 is still chalk with a definite basal nodule-bed. Where the Chalk 

 comes in again below Pinhay, west of Lyme, the succession at the 

 junction of Chalk and Upper Greensand is as follows : — 



Section below Pinhay. 



Feet. In. 

 ,(7. Hard, rough, nodular chalk, with Inoceramus mytiloides, 



Cardiaster pygmceus, and Cidaris hirudo 1 9 



m j 6. Hard glauconitic chalk, with Inoceramus mytiloides and 



Cidaris hirudo 1 9 



5. Softer chalk, full of quartz and glauconite, with many 



phosphate-nodules and derived fossils at the base..., 9 



f4. Hard, rough, quartziferous limestone with large green-coated 



j lumps, fossils not abundant. About 1 



M. ■{ 3. Hard, compact, shelly limestone, fine-grained above, but 

 | coarse and quartzose at the base, which rests on an eroded 

 ^_ surface of the bed below 1 6 



{2. Calcareous sandstone with few fossils, indurated and calcified 

 in the upper part, softer below 8 

 1. Chert-beds, fine sandstone with irregular concretions of 

 chert, seen for 22 



These beds fall into three natural groups as bracketed, which we 

 may for the present call G, M, T. 



Group G is clearly the higher part of the Upper Greensand, and 

 the calcareous sandstone occupies the place of the similar bed in 

 Dorset. Pecten asper has not been found in it, but the fossils which 

 do occur are those of its Dorset equivalent. 



Group M. — All the beds above the calcareous sandstone are very 

 variable in thickness. Nos. 3 and 4 are in one place less than a 

 foot thick, but expand in a short distance to more than 3 feet. 

 The lower bed contains a mixture of fossils which are elsewhere 

 characteristic of separate zones; some of the so-called 'zone of 



