118 



1. Black Shales... 



2. Bone-bed 



3. Black Shales .. 



4. Lower Pecten-bed 



5. Black Shales... 



6. Upper Pecten-bed 



7. Black Shales... 



8. Estheria-bed ? 



9. Monotis-bed? 



4 feet. 



1 foot 5 inches. 



9 feet. 



8 or 9 inches. 



7 feet. 



7 or 8 inches. 



3 to 4 feet. 



4 inches. 

 10 or 12 inches. 



To these succeed a series of Shaly beds, having intermittent bands of grey- 

 stone, intercalated in the lowermost layers abounding in Ostrea liassica, 

 Modiola minima, Cardium, and Myacites. 



At the Southern extremity of the excavation, the beds above the Upper 

 Pecten-bed were examined, and the following succession tabulated in 

 ascending order : — 



1. Black Shales 



2. Indurated Marls 



3. Compact Limestone band 



4. Shaly Limestone 



5. Intermittent band, containing Cardium | 



rhceticum ... ... ... ) 



6. Compact dark-coloured Limestone con- \ 



taining comminuted Shell ... ) 



7. Shaly-beds, assuming a more compact | 



structure in the upper layers ) 



8. Ostrea liassica beds 



Till' following list of fossils from the bed marked 7 was noted : — 

 Area, sp. 

 Lima punctata. 

 Modiola minima. 

 Cardium rhceticum. 

 Axinus, sp. 

 Together with many other Rha^tic formf^. 

 Tliese shales, together with the under-lying limestones, were assigned by 

 the geologists present to the " White Lias," to which, from their position 

 and contained fossils, they were adjudged to belong. 



The fine section at Pennarth Head displays the whole series of beds at 

 one view. Here, upon a Keuper base of great thickness, seamed through- 

 out with white layers of gypsum, the Rhaetic and Lower Lias beds are 

 exliibited in a grand escarpment calculated at not less than 200 feet. 



This is a A^ery valuable section, and when compared with those at 



1 foot. 



6 inches. 



1 foot 4 inches. 



1 foot. 

 4 inches. 

 12 feet. 



