454 ME. H. BOLTON ON A MAKINE PATINA IN THE [NOV. 1907, 



Thickness in feet inches feet inches. 



13. Shales and Grits: 



Fireclay 4 6 



Mudstone 15 



Greyish grit L 3 



Micaceous shale 1 7 



Mudstone , 16 6 



Grit with shale-partings 2 9 40 7 



14. Marine Band (chief shell-bed) 19 10 



15. Shales and Grits: 



Grit 1 6 



Mudstones 11 12 6 



16. Shale (Marine Band) 3 8 



17. Shales and Grits: 



Black shale 37 6 



Grit 1 9k 



Mudstone 12 0^ 



Shale 6 6 57 9| 



18. Grits and Mudstones: 



Massive grit .13 4 



Mudstone 17 9 



Conglomerate-grit 3 6 



Shale 3 2 37 9 



19. Bastard Coal : 



20. Sandstones and Shales: 



Sandstone 8 4| 



Conglomerate-grit 4 2 



Black shale 3 



Fireclay 6 16 0^ 



Millstone-Grit Series. 



21. Grits, with shale-parting: 



Hard grit 34 10 



Shale 4 



Massive grit 32 10 68 



22. Mudstones and Grits: 



Mudstone 4 8 



Fireclay 4 2 



Mudstone 6 10 



Massive grit 4 6 



Mudstone 5 6 



Hard grit 5 6 



Mudstone 3 5 



Hard grit 7 6 



Mudstone 10 52 1 



23. Hard grit, with mudstone-partings ... 10 3 



Y. Pal^ontological Description. 



The marine fauna contained in the shales of the Ashton-Vale 

 Colliery is fairly extensive, including at least 38 genera and 47 

 species. . The most striking features are the dwarfing of many 

 forms and the reduction of shell-matter. This is especially the 

 case with the Brachiopoda and Lamellibranchiata. Gasteropods are 

 unusually numerous, but small, and even minute. Cephalopods, 

 including the generally robust Gastrioceras Listeri, are so thin- 

 walled that nearly all are found crushed ; and, with this reduction 

 in thickness of the shell-substance, there is an equally-marked loss 

 of character in the surface-ornament. Fish-remains are scanty, 

 and show the dwarfing to an exceptional degree — the tooth of 



