Page:Quarterly Journal of the Geological Society of London, vol. 25.djvu/432

322 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 9, are Old-Red-Sandstone conglomerate. Striated boulders of brown sandstone of great size lie scattered about the lower slopes; and at Kilaornan burn these brownish grits and argillaceous flags occur in situ, and form the material of the neighbouring Pictish tower. The next stream northward is Craggie burn. Here the flaggy gneissose rocks reappear, dipping E.S.E. at a high angle, associated with thin seams of the quartzo-felspathic rock c. No gold has been found in Loth-beg Water, nor in the Kilaornan burn; but Craggie burn has proved auriferous.

Strath Ullie.

In the bed of the Ullie or Helmsdale, above the Crask bridge, and near Kil-Donnan Lodge, flaggy micaceous and gneissose beds are traversed by granite b, which is itself intersected by a dyke of dark brown trap. This crosses the strata and associated crystalline rock, but without affecting the dip, which is here N.E. (fig. 3). Further up stream the schistose rocks become harder and more flaggy in character, and the dip changes slightly to the eastward, unaffected apparently by the presence of the granitic rocks, which occur as thick bands, throwing out veins in all directions, which sometimes follow the seams, and suddenly cease when about an inch thick (fig. 1). Very rich washings were found here in the rocky pockets by the river-side, the overlying drift being particoloured clay with white bands and blotches, covered with ferruginous gravel and sand.

Passing for the present the mouth of the Suisgill burn, which flows into the Ullie from the north, about two miles from this point, we reach the river Fri, flowing from the west. Here micaceous and gneissose flags dip E.S.E., with some intercalated granites. These, generally large-grained and friable, become more numerous as we proceed towards Achintoul, beyond which, in the Cnock-fionn river, running from the N.E., they become very abundant. Here the dip is still easterly and at a high angle. A little gold has been found in the stream last mentioned. Hereaway the country becomes deeply boggy, the first prominent rocks, about eight miles to the north-west being the lofty twin mountains Beinn-Ghriam-mor and Beinn-Ghriam-beg, isolated masses of Old Red Sandstone, dipping S.W., and furnishing most imposing evidence of immense denudation.

Returning from Achintoul by the Strath-Ullie road, five miles bring us to Cinn-preas burn, a north-eastern tributary of the Ullie. Here red granitiform rocks and flaggy beds occur, dipping east. A small nugget, weighing 5 dwts., was found here, and a good deal of granular gold.

Suisgill, the next stream from the north-east, was early visited by the diggers, and is still their favourite resort. The gold found here is generally in larger pellicles, and has hitherto been sufficiently abundant to yield a very fair return for skilled labour. Flaggy gneissose rocks, with a few micaceous beds, dip here E. and E.S.E.; but the feature of its lithology is the abundance of a binary com-