Coast- cliff Den uda tions. 487 



it with a geological eye, it is obvious that a great num- 

 ber of similar landslips have taken place in times past, 

 of which we have no special record. 



In the north country the same kind of history is 

 plain all along the Liassic and Oolitic cliffs of York- 

 shire, on a coast formed of almost the finest cliffs in 

 England. Not very many years ago at Rosedale, on the 

 north horn of Runswick Bay, an important set of iron 

 works, offices and cottages, with a pier and harbour, 

 were by a landslip at night utterly ruined and borne 

 into the sea. The slight seaward dip of the strata, 

 composed of clays and sands, ought to have warned the 

 proprietors of the insecurity of the position of their 

 works, had they possessed sufficient geological know- 

 ledge. 



In parls of our country in the west, the Silurian 

 rocks, Old Red Sandstone and Coal-measures on the 

 coast, show equal evidence of waste, though much 

 slower in its progress ; as for instance at St. Bride's 

 Bay, in Pembrokeshire (see Map), where the north and 

 south headlands are formed in great part of hard 

 igneous rocks that stand boldly out seaward ; while 

 between these points there are softer Coal-measure 

 strata, which once filled what is now the bay and 

 spread far beyond. But because of their comparative 

 softness they have been less able than the igneous rocks 

 of the headlands to stand the wear and tear of the 

 atmosphere and the sea waves, and thus having been 

 worn back a large bay is the result. I know of no place 

 in Britain where the effects of long-continued marine 

 denudation can be better marked than in this part of 

 Pembrokeshire. Let the observer cross to Ramsey 

 Island, opposite St. David's, and ascend one of the 

 rocky hills. Below he will see that a large part of the 



