OLD RED SANDSTONE OF WESTERN EUROPE. 427 
the stones are mostly well water-worn. But with so little trace of stratification 
have these coarse materials been accumulated, that it is often only when we 
retire from the front of a cliff, and look at it as a whole, that we can make out a 
general gentle inclination down the valley. Large oblong stones may often 
indeed be found stuck on end in the conglomerate, or tilted up at a high angle. 
A marked structure in some parts of the conglomerate, particularly observable 
in the gorge of the small brook which joins the left bank of the Avon near its 
union with the Ailnack, is a kind of false-bedding of the stones. Between the 
gently inclined lines which mark the true dip, the stones of each bed of con- 
glomerates are arranged in a rude stratification obliquely across the line of the 
valley at angles of 17° to 20°. They thus appear to dip towards the hills, while 
the true inclination of the conglomerate beds is away from them. The stones 
are all derived from the waste of the metamorphic rocks, quartz-rock being 
particularly abundant. At several points the conglomerate may be seen 
resting upon and wrapping round knobs and stacks of the reddened schists 
and slates, indicating on what a very uneven rugged surface it was de- 
posited. . 
There can hardly be any doubt that this outlying portion of the Old Red 
Sandstone was formed either in a long valley connected with the main area of 
deposit to the north, or in a separate and isolated hollow. In neither case does 
it necessarily imply the denudation of the Old Red Sandstone from a wide 
extent of country. Undoubtedly it has suffered greatly in the general waste of 
land since palzozoic times, so that we can but dimly perceive what must have 
been the original physical geography of the district. Nevertheless, it is not an 
outlier like Morven or the Ben Griam hills, where mountains are capped with 
conglomerate, which must assuredly have had formerly a far wider extension. 
The worn and trenched slopes which rise on either side of the Tomintoul patch 
of conglomerate doubtless represent still the slopes of the hollow or valley, 
whether of lake or river, in which the coarse shingle of that deposit was accu- 
mulated. 
I am not aware that any other outliers of the Old Red Sandstone occur in 
the interior, though a few patches of small size may yet be found in their 
original hollows along the northern slopes of the Grampian range. Turning 
therefore to the coast-line, we find that the continuous belt of this system, which 
skirts the Moray Firth from Loch Ness to Buckie beyond the mouth of the 
Spey, is prolonged eastward by a number of detached patches—the broken 
fringe of deposits which probably exist in a continuous sheet underneath the 
sea to the north. | 
Of these outliers the most easterly, and, at the same time, by far the most 
important, is that which stretches along the coast from Gamrie to Aberdour, 
and extends inland for upwards of 15 miles. This patch though long known to 
