38 Lincolnshire Notes & Queries. 



immeasurably further back, over " the great dragon land," and 

 picture again in thought the teeming life of the old Liassic sea. 



AND now, having completed the building of the land 

 between Gainsborough and Lincoln, I will, as briefly as 

 possible, try to show how it attained its present shape. 



To understand this we must first glance a little further to 

 the east, where, after passing over the limestones and clays of 

 the higher Jurassic seas, we reach the chalk wolds. 



In these cretaceous strata we have the remains of beds 

 which must have been laid down in great ocean depths, for 

 there only are similar deposits being formed in our own day. 



The Atlantic ooze, the modern equivalent of the chalk, is 

 not deposited at a less depth than about 1,000 feet, and usually 

 much deeper; and as this ooze is laid down, according to the 

 Challenger calculations, at the rate of a foot in a century 

 at the most, the chalk, which is now some 1,300 feet thick, 

 and had at one time another 1,000 feet at the top of it, which 

 has since been swept away, the time occupied in the formation 

 of these chalk beds must have been enormous. At the above 

 rate of a foot of sediment in a century, the lost 1,000 feet 

 alone would have taken 100,000 years to form. 



Now, that the neighbourhood of such an ocean as this, 

 which reached from Ireland over Europe to the Crimea, should 

 have greatly affected the area we are considering, is not to be 

 wondered at. 



For a long period, during the existence of the Oolite and 

 higher Jurassic seas when the land to the east of Lincoln, 

 between it and the chalk wolds, was being formed the 

 Triassic, Rhoetic, and Lias beds on the west had become dry 

 land ; but as the chalk sea grew, the weight of its deposits 

 caused the land all round to sink, and as this sea at last covered 

 nearly the whole of England and Wales, the district between 

 Gainsborough and Lincoln, with all the western land, was 

 buried far beneath its waves. 



Now the action of a sea is always that of a leveller, and as, 

 in course of ages, the cretaceous ocean itself passed away, the 

 land beneath it, as it rose again to the surface, presented a 

 smooth plane of erosion, gradually sloping up to the higher 

 lands around, which had, during this epoch, remained dry 

 ground. 



At this time a period when the Pyrenees were thrown up 

 England, Scotland, and Ireland were probably, as Mr. Jukes 

 Browne tells us, bound together in one mass. Land lay far 



