64 



3rd. cent. M.S. or J Depression of sub-aerial volcanic deposits beneath 



Vol. Til. mixsing. \ the sea, with deundation. 



2nd. cent. M. S. or J Period of great volcanic activity, volcanoes at first 

 II. t 



Vol. II. ( sub-marine, afterwards .sub-aerial (12,000 ft.) 



;ent. M.S. or ( Prolonged depression and accumulation of .Skiddaw 

 Vol. I. \ Slates, marine shallow-water deposits (10,000ft.) 



