EAST MIDLAND DISTRICT. 73 



in extent, and owing to the confusion and crushing of the rock, it is not easy to 

 trace their relation to the Terebratula-beds, which are seen farther up the line 

 (towards the south). It is by no means easy to say whether these beds are on 

 precisely the same horizon as those at "Weldon. The general character is the same, 

 but each has its peculiarity. At Weldon, for instance, Monodonta laevigata swarms ; 

 here it seems almost absent. The species of Nerincea too seem to differ, but where 

 all, or nearly all, are so much rolled, the question of the Neringeas of the Lincoln- 

 shire Limestone is not one calculated to give much peace of mind to a palseonto- 

 logist. 1 



Barnack is another place which has yielded in former times a considerable 

 number of these small Gasteropoda. At present what few fossils can be obtained are 

 picked up on refuse heaps. There are many other quarries in Northamptonshire, 

 Rutland, and South Lincolnshire which have yielded here and there a few good 

 fossils. Some of these quarries are undoubtedly on the horizon of the Oolite Marl ; 

 as regards the others I have no evidence. One thing must strike the most casual 

 observer, and that is the extraordinary difference between the Gasteropod Fauna of 

 Dorsetshire, and of the Lincolnshire Limestone. Some forms, it is true, are merely 

 micromorphs of species occurring elsewhere ; but even granting that, the contrasts 

 are enormous. 



North of Grantham I have no knowledge of the Lincolnshire Limestone, or of 

 its fossils, with the exception of a very few specimens now in the Jermyn Street 

 Museum. Should I subsequently discover any notable quantity of Gasteropoda in 

 the Inferior Oolite of this region, it may be necessary to deal with the subject by 

 way of postscript. 



Failing other evidence, we must regard the Northampton Sand, the Colly weston 

 Slate, and, perhaps, the whole of the Lincolnshire Limestone, as belonging to the 

 Lower Division of the Inferior Oolite. 



1 The cuttings known as Little and Great Ponton, on the Great Northern Eailway, south of 

 Grantham, were described by Prof. Morris (' Quart. Journ. Geol. Soc.,' ix, 324) with considerable 

 detail, and these descriptions are quoted in Messrs. Jukes-Browne and Dalton's ' Geology of S.-W. 

 Lincolnshire.' These authors consider the thickness of the Lincolnshire Limestone in South Lincoln- 

 shire to be fully 100 feet. They regard it as a lenticular mass between the Lower and Upper 

 Estuarine, and further state that there is no constancy in the occurrence of the " coralline facies " 

 as distinct from the " shelly facies ;" since either may occur on any horizon. Mr. Brodie's observation 

 is quoted that the more marly layers are particularly rich in corals, and recall the facies of the 

 Oolite Marl at Crickley. 



10 



