-iS8o] 183 



however, yet believe in the r theory, for reasons which Is---* 5- : 



I will presently give. 



1 here arc three chief hostile considerations in Mr. Milnr- 

 paper. First, the Glen [shelf?], not coinciding in height with 

 the upper one [outlet?], from ob 1 5 ft., 



29 ft., 21 ft. : if the latter arc ;t the terrace mu.st be qu ' 



independent, and the ca c < but Mr. Milne shows that 



there is one in Glen I 4 ft. below the upper one, and a 



;ond one again ''which I beneath this, and then 



we come to the proper second shelf. Hence there is no great 

 improbability in an independent shelf having been found in 

 Glen Glu 



This leads me to Mr. Milne's -econd class of facts (obvious 

 to amely the non-extensi the three shelves 



beyond Glen Roy ; but I abide by what I have written on 

 that poirr repeat that if in Glen R :ere circumstances 



have been so fa >le for the p: 1 or formation of 



the terraces, a terrace could be formed quite plain for three- 

 quarters of a mile with hardly a trace elsewhere, we cannot 

 argue, from the non-existence of shelves, that water did not 

 stand at the same levels in other valleys. Feeling absolutely 

 convinced that there was no barrier of detritus at the mouth 

 of Glen Roy, and pre/ il convinced that there was none 



of ice, the manner in which the terraces die out when enteri: 

 Glen Spean, which must have been a tideway, shows on what 

 small circumstances the formation of these shelves depended. 

 With respect to the non-existence of - in other of 



Scotland, Mr. Milne shows that ma: :rs do exist, and 



their heights above the sea have not yet been carefully 

 measured, nor have even th' hich I suspect 



are all IOO feet 1 



we must not feel sure that cither the absolute height or the 

 intermediate hei ten juld be at all the 



same at dl.-tant points. -.he terraces in Lochab< 



all, I believe, have been taken in Glen Roy 

 There should b Is taken at right 3 to this line and 



to the Great Glen of Scotland or chief line of elevation. 



Thirdly, the nature of the outlets from the supposed lakes. 



1 '* On the Lines of Ancient Level of the Sea in Finmark. : By A. 

 Bravais, Member of the Scientific Commission of the Nort'.. \rt. 



Journ. Geo/. Soc, 



