338 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Juiie 15, 



Table III. — Exhibiting the varying thickness of the Clays in the 

 different sections. 



Oyster-bed and"! 

 marl}' rock... j 



Clays between ] 

 the above and > 

 the stem -bed. J 



Stem-bed 



Clays below \ 

 stem-bed ...j 



Iron-band .. 

 Oolitic rock 



Essendine. 



Aunby. 



Danes' 

 Hill. 



Little 

 Bytham. 



Creeton. 



ft. 



ft. 



ft. 



ft. 



ft. 



11 







16 



8 -1 



16 



9 



20 



6 



10 J 





2i 



3 



2 



1 



2' 



u- 



4 



7 



15 



10 J 



10 







present 



1 



1 



1 















10 



8 



Countiiorpe 

 or Swayfield. 



tt. 



14 

 1 



13 



With the close of the deposition of the white ooUtic rock, a new 

 series of conditions set in, indicating a change from marine to, if not 

 fluviatile, at least fluvio-marine action, the whole series of beds resulting 

 from a very slow and gradual accumulation of sediment, as proved by 

 the finely laminated appearance of many of the layers. Oscillations 

 of the surface must, however, have taken place, as the bituminous bands 

 infer a favourable condition for the growth of, perhaps, a marsh 

 vegetation, the roots proceeding downwards amidst the recently ele- 

 vated marine shelly mud, as seen in the continuous stem-bed of the 

 sections. The bands of Cyrena were very local and confined to the 

 lower portion of the series, being associated in some places with marine 

 shells, as a species of Mactra. Marine conditions succeeded to the 

 termination of the series, changes in the mineral matters occasionally 

 taking place, and a partial different distribution of organic forms ob- 

 tained, as seen in the layers containing numerous Necera, Pholadomya, 

 Cytherea, Cardium, &c., and scarcely any univalve testacea ; above 

 these beds again occurred an irregular muddy deposit, with numerous 

 remains of testacea attaining a full size ; amongst these are Modiola, 

 Cardium, Natica. A zone oi Pholadomya occurs in this part of the 

 series, the shells occupying their normal position. A thick deposit of 

 small Oysters, with a few other shells, terminated this succession of 

 strata, above which the Cornbrash series began to be deposited. 



We reserve for a future occasion the details of the data, obtained 

 by traversing the intervening district, upon which we consider the 

 synchronism of these marine and estuary beds of Lincolnshire with 

 the Bradford clay and Forest marble of the South established : and, in 

 considering them as the equivalents of the upper sandstone and shale 

 of Yorkshire, it may be observed, that marine remains occur but 

 rarely towards the close of the series in the latter area, the upper 

 beds being almost entirely destitute of organic forms, i. e. Testacea. 

 In a recent examination, however, of the coast of Yorkshire I found 



