88 
BY THE Rey. HENRY BRASS, M.A, F.G.S. 
Mr. Mackintosh’s idea derives strong corroboration from the comparatively 
recent formation of the deltas of the rivers of the Alps. 
For example, the delta of the Rhone, in the Lake of Geneva, has, 
according to Sir C. Lyell (Principles of Geology, chap. xvili., 8th ed.), 
increased “ more than a mile and a half,” “in about eight centuries.” 
He states that the remainder of the delta is “about five or six miles in 
length,” so that, at this rate, the delta is less than 4,000 years old ; and, as. 
it narrows and shallows towards its apex, even this estimate must be 
considerably reduced. 
Now, what was the river doing with its sediment before it commenced to 
form the delta? Possibly, as Lyell suggests, it was filling up some lake 
basins in the upper part of its course, but as the contents of these basins. 
(as I gather from frequent observation) do not much exceed (if they do at 
all) the contents of the delta, and as many of them may have been filling 
(partially, at least,) contemporaneously with it, we cannot but be forcibly 
impressed with the comparatively recent origin of the present physical 
condition of the country. 
Or, did the river (as some have conjectured) formerly flow through the 
Valley of the Trient into the Arve, at Chamouni? This would not have been 
possible without very great alterations of level, inasmuch as the Valley of 
Chamouni is about 2,000 feet higher than that of the Rhone at Martigny, and 
the lowest point between them is about 3,500 feet higher ! 
The most probable conjecture seems to be that the Great Rhone Valley 
was filled with ice, and that the Alpine glaciers extended down into the Lake 
of Geneva, a very few thousand years ago ; and that on, or soon after, the 
retreat of the glacier, the delta began to be formed. 
I wish that competent observers would work out this problem in the case 
of other Alpine deltas. 
With reference to the last paragraph of Mr. Mackintosh’s paper, I cannot 
but think that there 7s good historical evidence, that climate has been under- 
going a change. 
E.g.—(1) Job apparently dwelt in the land of the Crocodile and 
Hippopotamus (“ Leviathan” and ‘‘ Behemoth”), yet he mentions “ice” 
twice, “snow ” five times, and “ frost” three times ; and speaks of streams 
“blackish by reason of the ice,” and “the face of the deep is frozen ;” 
phenomena hardly to be found in those lands in the present day! (2) So 
also the way in which the old Roman historians and poets speak of the 
Winter seems to imply that the climate was much more severe in their day :-— 
e.g.—Horace (1 Odes, ix.) “. . . . geluque 
Flumina constiterint acuto.” 
Hard frozen rivers are certainly not characteristic of the Roman Campagna 
! 
now ! 
Livy speaks of armies going into winter-quarters as a general custom. 
