neighbourhood of Grantham. 257 



Patella rugosa, consisting of a coarse- grained oolitic freestone 

 lithologically resembling the shelly freestone in the Interior Oolite 

 at Leckhampton Hill. I was unfortunately so much hurried that 

 I had no time here to make sections, or to examine the quarries 

 more accurately. In a beautiful old Norman church lately 

 restored, at Tickencote in Rutlandshire, I noticed blocks of this 

 stone made up of minute shells in a good state of preservation, 

 similar to some on Minchinhampton Common. Crossing the 

 narrow lias valley to the opposite hill at Collyweston, which 

 commands an extensive view over the surrounding country, the 

 Stonesficld slate is largely quarried, and, as in the Cotswolds, 

 occupies the highest ground in the district. The following is a 

 section of one of the deepest quarries in descending order : — 



ft, in. 



1. Rubble, consisting chiefly of broken slate 5 



2. Sand, a few inches. 



3. Hard slate (ragstone) /.,,.,.. 4 



4. Yellow sand :'!7:':V'. . 3 



5. Slate ..:... 1 



6. Yellow sand 1 



7. Bluestone, with traces of vegetable matter in fragments . . 16 



8. Slate 3 



18 6 

 Further on some inferior strata are visible, viz. : — 



9. Sand 4 



10. Ferruginous oolite 14 



11. Clay 



Total 36 6 



The beds seem to be nearly horizontal. 



The best slate splits into thin laminoe, and forms a beautiful 

 and useful material for roofing, preferable even in some respects 

 to that of the Cotswolds, being finer-grained and more micaceous j 

 but the average thickness of the whole is about the same. There 

 is however a sufficient lithological resemblance to identify this 

 formation in Northamptonshire with that of Gloucestershire and 

 Oxfordshire ; and even the minor details are more nearly alike 

 than the distance of one deposit from the other would lead us to 

 suppose. The formation, however, near Stamford is by no means 

 so extensive in its geographical range, being, as far as I am aware, 

 limited to a few localities in that neighbourhood. I was unable 

 to trace the junction of the slate with either the Great Oolite 

 above, or the Inferior Oolite below, but it may be observed (ac- 

 cording to Mr. Morris) in one or two places in this district. I 

 cannot state positively whether it is as closely connected with the 

 Great Oolite as it is in the Cotswolds, where my friend Professor 

 Buckman and myself (in a joint paper on the Stonesficld Slate 



