58 Preston : Lincolnshire Naturalists at Little Bytham. 



The solid geology of South Lincolnshire embraces the whole 

 of the rock formations between the Rhsetic beds and the Oxford 

 Clay, all of which had been seen on previous occasions, with the 

 exception of those lying above the I'pper Estuarine Clays, and 

 these were now to be examined. In the cutting an upper bed of 

 the Great Oolite Limestone was found to be made up almost 

 entirely of small Oyster shells, Ostrea sowerbyi and O. subrugulosa , 

 which were freely collected. 



Mr. Preston exhibited a number of Oxford Clay Ammonites 

 which he had collected from the Boulder Clay w hen the Midland 

 line was being" made, just at its crossing with the disused railway. 

 Amongst these, Mr. Keeping, of the Cambridge Woodwardian 



Section of Great Oolite Series in Midland Railway Cutting, Little Bytham. 



Museum, had identified Ammonites eugenii, A. dentatus, A.jason, 

 A. marice, and A. cordatus. Much interest was manifested in 

 examining a fault in the Great Oolites near this crossing of the 

 two railways, which could not be seen until the new- line was 

 being made a few years ago, because of the overlying Boulder 

 Clay. The fault is a normal one, strikes approximately N.E. 

 and S.W., and has a downthrow to the S.E. of about seven feet. 



Passing next along the old railway, some good sections of 

 Cornbrash were seen and examined, and several of the type 



Naturalist, 



