Natural History. 33 



Geologists divide the earth's strata, for convenience, into 3 

 great divisions Primary, Secondary, and Tertiary and as, in 

 Lincolnshire, we have representatives of the entire Secondary 

 series, from the strata above the Trias on the west to the 

 chalk on the east, this fact alone must give to the Geology of 

 the County a special interest and value. I am not, however, 

 going to speak of so wide an area now, but intend to confine 

 my address to the low flat land between Gainsborough and 

 Lincoln a distance of some 15 miles alluding to the adjoining 

 strata, only as they are necessary to explain the structure and 

 present configuration of the district. 



Now, as we stand on the high ground above Gainsborough 

 and look over the Trent, we are on the oldest strata in the 

 County the Upper Keuper beds as they are called at the 

 top of the Trias or new red sandstone, the highest beds in the 

 great Primary Division ; and if we could be carried back to 

 the time when these beds were laid down, we should see, 

 instead of the present country, a vast lake, or inland sea, 

 surrounded on all sides by land, which extended far out into the 

 Atlantic on the west, and was connected with Europe on the 

 south, and with Scandinavia, over what is now the North Sea 

 or German Ocean, on the east. 



This region had, for a very long period, been in a quiet, 

 tranquil state ; a great contrast to the stormy Permian age 

 which preceded it, when the Alleghany mountains of America 

 and the Pennine Chain of Derbyshire, the backbone of 

 England, were thrown up. 



This vast inland sea was a fresh-water lake, which gradually 

 became salt by the concentration of its waters, like the salt 

 lakes of North America, and in which sandstones, grey and 

 red marls, salt and gypsum were deposited. 



It is to this inland sea, barren as it was, that we owe the 

 rock-salt and brine springs of Worcestershire, Cheshire, and 

 Middlesborough : while, from its deposits of gypsum, or 

 hydrated sulphate of lime, we get ornamental alabaster and 

 plaster of Paris, from which Parian and other cements are 

 made. 



In the railway cutting leading to Lincoln, bands of blue, 

 red, and grey Keuper marls are seen, each resting on the other. 

 They are the slow and quiet products of this great inland lake 

 and have no traces of life left in them. Suddenly, however, a 

 wonderful change takes place j for, resting on the uppermost 



Vol. 5, No. 35, Lines. N. & %. c 



Nat. Hist. Sea. 



