682 J. W. JUDD ON THE SECONDAKY EOCKS OE SCOTLAND. 



logical key it is found that this portion of the British Islands must 

 at one time have been covered with an enormous thickness of strata, 

 intermediate in age between the Carboniferous and the Eocene. 

 This thick mass of strata, which in places attained probably to a 

 vertical thickness little, if any thing, short of a mile, was represented 

 by the following members, here shown in a tabular form, with their 

 maximum thicknesses : — 



Table showing the Succession of the Mesozoic Strata in the Western 

 Highlands. 



Maximum thickness. 



Miocene Volcanic and Inter- volcanic rocks. feet. 



Unconformity. 



1. Estuarine clays and sands, with coal 20 -f- 



2. White chalk with flints (Zone of Belemnitella mu- 

 Oretaceous ...-1 cronata) 10+ 



3. Estuarine sandstones, with coal 100 



Jit. Upper-Greensand beds 60 



Unconformity. 



(5. Oxford Clay ? 



Oolitic \ 6. Great estuarine series 1000 



[7. Lower Oolite 400 



f 8. Upper Lias 100 



9. Middle Lias 500 



10. Lower Lias 400 



11. InfraLias 200 



LlASSIC 



Poikilitic ... 12. Conglomerates, sandstones, marls, and limestones 1000-f- 



Unconformity ? 

 Carboniferous. Sandstones, shales, and coals. 



Unconformity. 

 Older Paleozoic ? Gneiss rocks and Torridon Sandstones. 



It will be seen from the above Table that while the Poikilitic, 

 the Liassic, the Oolitic, and Upper Cretaceous systems are all repre- 

 sented by deposits of very considerable thickness, several other mem- 

 bers of the Mesozoic series have not as yet been detected on the west 

 coast of Scotland. The principal formations found to be thus un- 

 represented there are the Upper Oolite and the Neocomian. 



But I would ask the reader to call to mind the evidences, which I 

 have already laid before this Society in a former communication, that 

 the Upper Oolites are represented in the Eastern Highlands by de- 

 posits of great importance (probably not less than 1000 feet in thick- 

 ness), and that there are some grounds for the inference that beds of 



