Cambridge Philosophical Socieii^ 



6a& 



,l:)J')imi 



,-!- \nu 



lo I '.17/ 

 -t il[ ¥\ 



;(l .1.;. 



>flt i[ 



b jflsis'^ I 



!h: 



feet. 



"{ ■•••* 



;>l<itt 



200 



300 

 300 



400 



450 

 600 

 800 



feet. 

 50 



50 

 100 



100 



150 

 150 

 200 



V. 



miles, 

 62 



73 



77 



86 



95 

 106 

 140 



"1- 



miles. 

 12 



10-4 

 19-4 



17 



23-5 

 20-5 

 28 



"3- 



miles. 

 5 



10 

 5 

 5 



10 



5 

 10 



10 



10 

 10 



8. 



l_ 



30 

 l__ 

 372 

 _/_ 

 52 

 _/^ 

 14 

 ji_ 

 34 



20 

 J_ 

 60 

 J_ 

 24 

 _^ 

 39 

 l_ 

 25 



nearly 



^n^ )i 



jnnr 



not t{ It 

 |.i!-t 'tu txi;q 



— nearly 



10 ^ 



^ j«0(jj5 



>.ifii iii 



I'lo yjt') >") 

 .i(.t ff'.itf >, 



.oolav 



1 H)l.)7 



which now exist between the original site of a block and its present 

 position, have been far too much insisted on by some geologists, 

 for, he contends, such inequalities could not generally exist under 

 the continued action of denuding causes, among the most powerful 

 of which may be reckoned the transporting currents themselves. 



It should be remarked, that it ajDpears from the values of s given 

 in the preceding table, that the space through which any consider- 

 able block could be moved by a single wave of elevation, is only 

 equal to a small fraction of the breadth of the wave. Consequently, 

 if such a block has been moved by this agency to a considerable di- 

 stance from its original site, the transport must have been eiFected by 

 a repetition of transporting waves ; and, therefore, since a wave of 

 considerable height can only be produced by a sudden elevation, this 

 theory of transport is ultimately associated with the theory which 

 attributes the more marked phsenomena of geological elevation to a 

 repetition oi paroxysmal movements. 



The author concludes with some general observations on the evi- 

 dence by which we may hope to distinguish between the effects of 

 the three different agencies to which the transport of blocks may be 

 attributed — glaciers, floating ice, and currents of water. Large an- 

 gular blocks in the immediate neighbourhood of glacial mountains 

 (such as the alpine blocks) may doubtless, in many cases, be referred 

 to glaciers, while the transport of similar blocks to great distances 



