hw 



« i 



t 



Sect. VL] 



GEOLOGY. 



179 



will 



Any person st: ^Jly atteiidiiig to tbese subjects 

 occasionally be enabled to form an opinion on poin 

 at first appearing hopelessly obscure to bim. 



ts 



Tbo com 



mon 



deep-sea lead, especially if made a little bell- 

 shaped and well armed, gives a surprisingly good picture 

 of the bottom. There can be no doubt that whoever 

 will for a long period collect and compare observations, 

 made over wide area& and under different circumstances, 

 will arrive at many curious, novel, and important results. 

 An observer occasionally may arrive at a district where 

 lately some great aqueous catastrophe has occurred, such 

 as the bursting of a lake temporarily formed by a slip, 



or the rush of a great 



1 



■'-\ 



-wave over low land. 



cases 



ness and nature of any deposit left— whether stratified 

 irregularly or continuously— whether any rocky surface, 

 over which the debacle has passed, be scored or smooth ; 



, and mea- 



all such points should be minutely described 

 suroments taken of any great blocks which may have 



been transported : the great desideratum is accuracy and 



minuteuuci. 



Ice Action. — The vovager in 



the Polar 



would 



render an excellent service to geology by observing all 



the effects which icebergs produce in rounuing, polishin 



g^ 



g solid rocks 



porting gravel and boulders. Fluatln 



ice under two 



rments 



I 



in whi-^^ the stranded boulders are frozen, and icebergs 

 formed by gbciers entering the sea^ on the surface of 

 v.hich masses of rock had previously fallen from the wur- 

 rounding precipices. It is obvious that in the latter case 



