100 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Julie 17, 



Cotteswold Naturalists' Club*, foremost amongst which the papers 

 of Strickland, Brodie, and Woodward may be mentioned. 



Even while the notes for this paper were being collected, Mr. Hull, 

 of the Geological Survey, has read a paper before our Society, has 

 completed the map of a great part of the Cotteswolds, and published 

 a ' Memoir of the Geology of the Country around Cheltenham, illus- 

 trating sheet 44 of the Geological Survey' : all these reflect the 

 highest credit on their author. 



Thus, these rocks especially, up to the Great Oolite inclusive, may 

 be considered as having had no small share of attention bestowed 

 upon them by different observers : not so, however, the beds above 

 the Great Oolite ; as the details of these, in so far as the counties of 

 Gloucester and North Wilts are concerned, have been but very par- 

 tially worked out ; and, indeed, the existence of the Oxford Clay in 

 the Cirencester district was a matter not understood until lately. 

 Here, then, it will not be out of place, if these Upper Oolite mem- 

 bers should receive a large share of attention. 



The Oolitic rocks which we shall have to review may be thus 

 tabulated in descending order : — 



13. Portland Oolite 





. Portlandia 



a . . Pervious to water. 



12. Kimmeridge Clay . 

 11. Coral Rag . . . 

 10. Oxford Clay . . 

 9. Kelloway Rock 







Oxfordian. 



. . Impervious. 



. . Pervious. 



. . Impervious. 



. . Impervious partially 



8. Cornbrash . . . 

 7. Forest Marble . . 

 6. Bradford Clay . . 

 5. Great Oolite. . . 

 4. Stonesfield Slate 

 3. Fuller's Earth . . 





J 



to 



1 



' 1 ^ 

 1 

 3 



. . Pervious. 



. . Impervious. 



. . Impervious partially 



. . Pervious. 



. . Pervious. 



. . Impervious. 























These rocks are all conformable, have a general dip from the 

 N.W. to the S.E., and have a very general evenness of stratification. 

 This, however, is not a little interfered with by a series of downcast 

 faults : these, and the alternations of pervious and impervious strata, 

 have given rise to a very undulating country, the long axes of the 

 valleys being for the most part in the line of dip, whilst a traverse in 

 the line of strike offers a constant succession of hill and vale. 



At the North Cotteswolds the elevation of the hills is more than 

 1 000 feet ; and here they offer bold scarps, overlooking the Vale of 

 Gloucester ; the scarps, headlands, and gorges in the hill-sides having 

 been formed by the water-action of the old Severn sea. As these 

 facts, however, relate to the physical geology of the district, I pro- 

 pose, in the first place, to give a description of the different deposits 

 of the Oolites, and then, in a future paper, to attempt a description 

 of the subsequent physical changes, — concluding with a detailed and 

 comparative list of the fossil contents of the different strata. 



See Proceedings of the Cotteswold Nat. Club, 1848-53. 



