Mr. BoGG on the Wolds of Lincolnshire. 395 



about twelve or fourteen yards: it forms a close measure, and I 

 apprehend supports the water collected by the open strata which 

 repose upon it, for water is always found either in the chalk or in 

 the ferruginous sand immediately below it, the well sinkers never 

 having occasion in this district to go deeper. 



The next in order, No. 5 of the section, is a stratum of grains 

 df quartz, which for the most part are conglomerated into sand- 

 stone of different shades of colour, from a dark brown to a light 

 grey, while in some places loose sand predominates. Marine shells 

 are found in this stone, each species, appearing to be restricted to 

 certain laminse of the stratum : in the sandy portions I have never 

 observed any organic remains. I consider this measure as con- 

 siderably thicker than either of the two incumbent ones, Nos. 

 3- and 4. 



I now come to the lowest visible stratum in our district, No. 6 

 of the section, which I term the shale stratum. It generally makes 

 its appearance in valleys, and its thickness I cannot estimate, for 

 I do not know where it exhibits any thing like a denundated ter- 

 mination. My brother (Mr. Thomas Bogg of Louth,) and myself 

 have bored in this stratum to the depth of a hundred yards near 

 the village of Donington, on the west side of the river Bain, and 

 found it to consist of the following varieties. 



3 D ^ 



