PROCEEDINGS-PERTHSHIRE SOCIETY OF NATURAL SCIENCE. XX11I 
the fallen trees, if not removed by human agency, might give rise to 
the formation of new beds of peat. The teachings of the spate 
were even more evident. A few days after its occurrence I had 
occasion to travel up the Highland line, and in passing up the valley 
of the Tay from Dunkeld to Ballinluig I had an opportunity of wit¬ 
nessing the enormous amount of geological work that the river had 
performed, both in its destructive and its constructive capacity, 
during its swollen condition. In this section of the valley the flood 
appears to have done more damage than any spate of recent years, 
and the results, from the points of view of the proprietor and the 
farmer, were certainly melancholy. The river had swept over the 
whole of the valley floor, breaking down embankments and fences, 
and carrying away both vegetation and soil in large quantities. But 
if the quantity of material carried away was remarkable, the material 
freshly deposited was still more so. Large areas of ploughed land 
were completely covered, in some places with layers of sand and fine 
silt several inches in thickness, and in others with beds of gravel and 
coarse shingle. The occurrence of these beds of varying degrees of 
coarseness side by side was very instructive, because it exactly corres¬ 
ponds with what we find when we examine an exposed section of an 
ancient accumulation of river deposits. It recalled, for instance, 
one of the cuttings I had examined a year or two before on the 
Crieff and Comrie Railway, where the line passes through a mass of 
river material which had been brought down by the River Turret in 
former times. In this cutting there were exposed many beds of 
finely stratified sand and silt, intermingled with layers of fine and 
coarse gravel, tapering off at either extremity, all precisely similar to 
the deposits just laid down at Guay and Dalguise. The recent spate 
has thus afforded one more lesson in the part which rivers play in the 
geological history of the earth’s surface, not only in transporting 
material from the land to the sea, but in re-arranging the material 
on the surface of the land itself. I firmly believe that as geologists 
come to examine more minutely the beds which make up the floors 
of our valleys, they will attribute less to glacial and lacustrine agency 
and more to the slow but perpetual action of the rivers. The well- 
known words of the late Poet Laureate—• 
“ Men may come and men may go, 
But I go on for ever ”—■ 
have a deeper significance for us when we penetrate even a little way 
into the secrets of Nature’s great laboratory, and see the working of 
some of the tools by which the Creator makes the surface of the 
earth both beautiful and fruitful. 
As regards the geology of Perthshire, by far the most important 
event that has occurred during the past year is a discovery by Mr. 
B. N. Peach, of the Geological Survey, which promises at last to 
throw some light on the age of the crystalline rocks of Highland 
Perthshire. In my address to this Society at the beginning of last 
session I mentioned that Sir Archibald Geikie had just then placed 
these rocks in a group by themselves under the provisional name of 
“ Dalradian.” I am sure, however, that no one will be better pleased 
