Pratt and Smith : Petroleum Resources.] 



[Phil. Journ. Sci., VIII, A, No. S. 





Fig. 1. An outcrop of Cudiapi sandstone. 



Fig. 2. An outcrop of Canguinsa sandstone. 



Fig. 3. Nearly vertical Vigo shale. 



Fig. 4. An outcrop of volcanic agglomerate. 

 PLATE X. 



