THE GEOLOGY OF SOUTH-EASTERN KINCARDINESHIRE. 953 
uncertain fashion the treatment to which they were subjected before they were finally 
buried in the wonderful gravels of Old Red Sandstone times. The conglomerates, 
whether we regard them as old beaches or as stream gravels, and the finer sediments 
with their prevalent ripple marks and sun-cracks, can only represent shallow water 
conditions; the association of remains of myriapods and plant debris in the latter 
undoubtedly indicates deposition in close proximity toa land area. The formation offers 
no evidence either of marine or of deep-water conditions of sedimentation. 
The composition of the conglomerates shows clearly that, throughout the whole of 
Lower Old Red Sandstone times, the Highland area was undergoing extensive denudation. 
The extraordinary abundance of jaspers, cherts, and “ green rocks” as pebbles in the 
lower conglomerates necessitates a former wide extension of the Upper Cambrian rocks 
—they may, indeed, have extended far over the Eastern Highlands. The frequent 
occurrence of boulders of the “‘ Haggis rock” type of greywacké, again, may mean that 
Ordovician strata (now probably represented by the narrow belts which Mr Barrow has 
designated the Margie series) were present in considerable force on the north side of 
the Midland Valley. In the conglomerates below the Crawton lava zone there is an 
alternating predominance of pebbles of Upper Cambrian rocks and of acid andesites, 
and this suggests that at successive periods the supply of Jasper and Green-rock material 
was temporarily cut off by the discharge of acid lavas from the Highland group of 
volcanoes. The distribution of granite boulders, too, is of supreme interest ; and, while 
I cannot at present give a detailed account of this, the occurrence of pebbles of granites 
belonging to the so-called “newer granite” types of the Highlands in the lowest con- 
glomerates is sutticient to show that some at least of these are of pre-Old Red Sandstone 
age. Such granites may represent the plutonic equivalents of the oldest “‘ Caledonian ” 
voleanics, which, as I have shown, are certainly not younger than the Downtonian, 
and may perhaps be older. The most striking characteristic of the youngest conglom- 
erates is the marked predominance of pebbles of flaggy gneisses, and along with this 
may be noted the gradual decrease in the proportions of those of jaspers and cherts and 
acid voleanic rocks as the former increase in number. Hence, towards the end of the 
period the ‘“‘ Highland Border” rocks and the Upper Silurian-Old Red volcanic series 
had either been protected by the overlap of the highest beds to the north and west, 
or had already been to a large extent removed by denudation. 
Conclusions such as the above are suggested by the general observations recorded 
in the present paper. It is hoped that further detailed investigation of the distribution 
of the boulders in the conglomerates will throw important light on the history of the 
Kastern Highlands in early paleozoic times. 
Nowhere in Kincardineshire does the distribution and character of the volcanic 
conglomerates suggest the destruction of volcanic islands and the consequent formation 
of coarse beaches. The constant association of “Highland” boulders with those of 
volcanic origin, and the thickening of the volcanic conglomerates when traced towards 
the Highland fault, point conclusively to the Highland area as the source of the 
