62 TOWN GEOLOGY. [n. 



would well say) their " tliouglit play freely " about it ; 

 and consider for themselves what those shells must 

 mean. I say not may, but must, unless we are to 

 believe in a " Deus quidana deceptor," in a God who 

 puts shells upon mountain- sides only to befool honest 

 human beings, and gives men intellects which are 

 worthless for even the simplest work. Those shells 

 must mean that that mountain, and therefore the 

 mountains round it, must have been once fourteen 

 hundred feet at least lower than they are now. That 

 the sea in which they were sunk was far colder than 

 now. That icebergs brought and dropped boulders 

 round their flanks. That upon those boulders a sea- 

 beach formed, and that dead shells were beaten into it 

 from a sea-bottom close by. That, and no less, Moel 

 Tryfaen must mean. 



But it must mean, also, a length of time which has 

 been well called "appalling." A length of time 

 sufficient to let the mountain sink into the sea. Then 

 length of time enough to enable those Arctic shells to 

 crawl down from the northward, settle, and propagate 

 themselves generation after generation ; then length 

 of time enough to uplift their dead remains, and the 

 beach, and the boulders, and all Snowdonia, fourteen 

 hundred feet into the air. And if anyone should 

 object that the last upheaval may have been effected, 

 suddenly by a few tremendous earthquakes, we must 

 answer We have no proof of it. Earthquakes up- 

 heave lands now only by slight and intermittent 

 upward pulses; nay, some lands we know to rise 

 without any earthquake pulses, but by simple, slow, 

 upward swelling of a few feet in a century ; and we 

 have no reason, and therefore no right, to suppose that 



