1857.] buckman oolites. 101 



2. Inferior Oolite. 



Basement-bed. — The line of separation of the Lias and the Oolites 

 along the whole of the Cotteswolds has always appeared so well 

 marked, both from structure and fossils, that until lately no prac- 

 tical geologist has had the least difficulty in the matter ; recently, 

 however, from some papers by Dr. Wright, we notice an attempt to 

 disturb the classification of the Upper Lias and Lower Oolitic beds, 

 respectively, as laid down by previous observers ; this writer con- 

 tending that the so-called Oolitic Sands and a few feet of compact 

 stone, very oolitic in structure, should be placed with the Upper 

 Lias. Here, then, at the very outset of a description of the Oolitic 

 rocks I find myself obliged to do battle for an important portion of 

 territory, which is attempted to be added to the Lias upon grounds 

 which, if admitted, I conceive can only end in merging the whole of 

 the Oolites into a Liassic series. 



Without following Dr. Wright through his elaborate paper* — 

 which I cannot help considering as a clever example of special plead- 

 ing, — I shall endeavour shortly to review the case as it stands. 



When, in 1834, Sir R. Murchison penned his * Outlines of the 

 Geology of the Neighbourhood of Cheltenham/ he for the first 

 time divided our inferior Oolitic rocks into distinct beds ; and in the 

 second edition of that work, which I had the pleasure of editing, 

 this classification was only altered by way of a still greater division 

 of the beds. 



It now, however, becomes evident that the descriptions adopted 

 in this work, taken, as they were, from the immediate neighbourhood 

 of Cheltenham, such as Cleeve and Leckhampton Hills, are only 

 locally correct, and more particularly as regards the basement-bed 

 of the Inferior Oolite. 



In the work mentioned we find the following remarks : — " The 

 lowest member of the Inferior Oolite has a remarkable mineral 

 aspect ; it is of a rusty brown colour, and is in great part made up 

 of small flat concretions from a quarter to half an inch in diameter. 

 It is called 'pea-grit' by the country people." And further on : — 

 "Coralline bodies are spread over 'the iron-shot faces of the beds 

 below Cleeve Clouds." Now this description of the basement-bed 

 of the Inferior Oolite defines it with tolerable accuracy for the district 

 referred to, as at Leckhampton the ferruginous more or less pisolitic 

 beds rest immediately on the stiff blue micaceous bands of the Upper 

 Lias. The following is the section : — 



ft. in. 



5. Shelly Freestone (Brodie) • • 1 in n 



4. True Pisolite / 1U U 



3. Coarse-grained Oolite, more or less pisolitic 13 



2. Foxy-coloured ferruginous Oolite, seldom pisolitic 20 

 1. Upper Lias shale. 



The late Hugh Strickland, in the * Geological Journal,' vol. vi. 

 p. 242, gives a complete section of the Inferior Oolite ©f Leckhamp- 



* Quart. Journ. Geol. Soc. vol. xii. p. 292, &c. 



