-----------------+------------------+-------------------+----------------- Gloucestershire, | South | N. | &c. | Northamptonshire | Northamptonshire | Yorkshire | | and Lincoln | -----------------+------------------+-------------------+----------------- Cornbrash | Cornbrash | Cornbrash | Cornbrash -----------------+------------------+-------------------+----------------- Great Oolite | Great Oolite | Great Oolite Clay | | (Upper part) | Great Oolite | Upper | | Limestone | | | Upper | Estuarine | Northamptonshire | Estuarine | ............... | ................ | ................. | ................ | | Series | Series | | Lincolnshire | Scarbro' | | Limestone | Limestone | Sands | | Middle Estuarine | | | Series Inferior Oolite | | Lower Estuarine | Millepore Oolite | | Series | | | | Lower Estuarine | | | Series -----------------+------------------+-------------------+----------------- Upper Lias | Upper Lias | Upper Lias | Upper Lias -----------------+------------------+-------------------+----------------- The dotted line shows roughly the division between Bathonian and Bajocian. The changes may be explained very simply if we leave out of account for the moment the development of Lincolnshire Limestone, with its equivalent the Scarbro' Limestone, and the Millepore series. The beds in Gloucestershire and other south-western counties are essentially marine; whilst in Northamptonshire and Lincolnshire estuarine conditions set in after the deposition of the Upper Lias, and continued throughout the deposition of the Bajocian and Lower Bathonian beds, being replaced by marine conditions during the formation of the Upper Bathonian strata, and still further north in Yorkshire the estuarine conditions generally prevailed throughout Bajocian and Bathonian times. These changes point to the existence of land towards the north. The general simplicity is modified by temporary prevalence of marine conditions twice over (during the deposition of the Millepore Oolite and the Scarbro' Limestone) in Yorkshire, and once (during the deposition of the Lincolnshire Limestone) in Lincolnshire.