510 
blocks of stone interspersed through the substance and poised upon 
the surface of morains. 
Within the records of history the lower terminations of many gla- 
ciers have varied considerably, and the morains left by them in the 
valleys show the extent to which the ice has descended in times 
comparatively modern. Agassiz has recognized the association of 
similar residuary phenomena not only in valleys of the Alps below 
the level of the present glaciers, but along the whole south-east 
flank of the mountains of the Jura, which run parallel to the Alps at 
the distance of fifty miles on the north-west side of the great valley 
of Switzerland. He finds on the Jura limestone, at various heights, 
from the level of the Lake of Neufchatel to three thousand feet, evi- 
dences from which he infers that glaciers descending the great 
valleys of.the Alps have extended across the entire valley of Swit- 
zerland over the lakes of Neufchatel and Geneva (then converted 
into ice), until their course was stopped and deflected in directions 
parallel to the Jura by the obstructing barrier which this mountain- 
chain presented. These evidences consist, 1st, in erratic angular 
blocks of the granite of Mont Blane, and other rocks from the high 
Alps, lodged on the south-east face of the Jura in insulated positions, 
and frequently upon banks of sand and gravel analogous to the mo- 
rains now forming in the Alps; 2ndly, in the frequent occurrence of 
polished surfaces, strize and furrows on the Jura limestone, similar to 
those now produced at the bottom of existing glaciers; 3rdly, in the 
coincidence of these striae with the direction in which a glacier from 
the Alps would have been deflected by the barrier presented to it 
by the Jura, and their non-coincidence with the slope of these moun- 
tains; 4thly,in the existence upon the polished surfaces of the Jura, 
limestone of funnel-shaped cavities (couloirs), and small indentations 
similar to the lapiaz we see daily forming at the bottom of glaciers 
by small and temporary cascades descending through cracks and 
chasms of the ice. 
M. Agassiz contends, that this quadruple series of phznomena, 
which are common to the south-east slopes of the Jura, and to the 
bottom of existing glaciers in the Alps, is inexplicable on any 
theory of aqueous action apart from ice; and still further argues 
that the concurrent appearance of similar phenomena in other re- 
gions of the world justifies the inference that these also have been 
the site of glaciers. He moreover infers, that very large portions of 
the now temperate regions of the globe have for a long period been 
enveloped with a winding-sheet of snow and ice. 
In November 1840, the evidence of the existence of glaciers in 
Scotland and the north of England has been brought before us in 
three communications: the first detailing the observations of M. 
Agassiz and Dr. Buckland conjointly during a recent tour in Scot- 
land ; the second recording Dr. Buckland’s observations in Scotland, 
Northumberland, Cumberland and Westmoreland; and the third 
containing evidences of glacial action collected by Mr. Lyell in 
Forfarshire and the valley of Strathmore. 
The phenomena in Scotland, wherein M. Agassiz and Dr. Buck- 
