irOOEE AB^'OEMAL SECONDARY DEPOSITS. 



481 



at which this bed had been recognized was at Batcombe, near 

 Bruton, eight or nine miles to the south. 



A coal-shaft has lately been sunk at Holwell Farm, near Mells, on 

 the property of the Rev. J. S. H. Horner, commencing in beds which 

 are mapped as Inferior Oolite. Immediately to the south, at Mells, 

 are Dolomitic Conglomerates of great thickness, which rest upon or 

 against the Carboniferous Limestone of the Mendip range. Almost 

 close to the pit are the Carboniferous limestones at Yobster, enclosed 

 on the south and south-west by nearly vertical Coal-measures. From 

 the '' old men's " workings around, it was expected that coal would 

 soon be reached ; but before this the very interesting and unexpected 

 section given below was passed through. 



After passing through 18 feet of rubbly sandstone and clay, which 

 graduated into a micaceous marl, the miners reached a rock which 

 was described as dense and unstratified, and one with which they 

 were quite unfamiliar. On specimens being sent me, I at once re- 

 cognized, by its lithological structure alone, the presence of the 

 marlstone, which was confirmed by the abundance of its characteristic 

 fossils. Amongst these were Ammonites spinatus, Pholadomya am- 

 higua, Belemnites paxillosus, and a Montlivedtia, the first coral found 

 in the Marlstone of this district. In the blue marl above I found 

 a perfect example of 0])liioderma Egertoni, fine examples of which 

 occur in a similar micaceous marl on the Dorsetshire coast. 



Section of a Coal-shaft at Mells. 



ft. in. 



1. Soil 1 



Inferior Oolite ? 2. Sandstone and sand 5 



f 3. Grrey variegated clay 5 



Middle Lias . . -| 4. Blae marl 7 8 



\^ 5. Middle Lias marlstone 9 



( 6. Fire-clay 3 6 



7. Coal 4 



8. Fire-clay 2 



9. Coal 1 



10. Bord binds with balls of mine .... 14 6 



11. Grey metal 8 9 



12. Fire-clay 1 



13. Coal 6 



14. Clod 1 



15. Coal 1 



16. Bord Cliff 5 



17. Mine 3^ 



18. arev metal 6 6^ 



19. Bord Chff with balls of mine .... 7 3 



I 20. Grey metal 3 6 



\21. Coal 10 



&c. &c. 



Coal-measures . . \ 



IV. Abnormal Secondary Deposits tjpon the Carboniferous 



Limestone. 



The description I have given of the horizontal stratified deposits 

 beyond the Mendips, and of their unconformable conditions within its 

 coal-basin, will better enable us to understand the very interesting 



VOL. xxiiT.— part I. 2 1. 



