THE GEOLOGY OF SOUTH-EASTERN KINCARDINESHIRE. 939 
the same type as the andesite of Carlin Crag, it seems fairly certain that it is on the 
same volcanic horizon as the Strathlethan Bay zone. 
The only fossils obtained from the Dunnottar group are specimens of Parka sp., 
collected from a grey sandstone associated with the tuffs at Strathlethan Bay. 
From Stonehaven harbour to the middle of Old Hall Bay the general direction of 
strike is east-north-east and west-south-west, while the strata are vertical or very 
highly inclined. In the section on the foreshore in the southern half of Old Hall Bay 
the angle of dip falls very rapidly, until at the extreme south corner it averages about 
35°. South of the next important headland, Maiden Kaim, the beds swing round the 
great synclinal fold of Strathmore, the strike changing to north-west and south-east, 
and the average angle of dip falling to 25°. 
B. The Crawton Group. 
The Crawton group is characterised by a marked increase in the proportion of 
volcanic rocks, quartzite conglomerates no longer predominating as in the underlying 
series. Detailed mapping has shown that it presents markedly different suites of lavas 
on the two sides of the Strathmore syncline. The area occupied by the northern limb 
of the fold contains a fine development of acid andesites; along the southern limb 
there occurs a remarkable group of porphyritic basalts. 
(a) The Crawton Basalts and Associated Rocks.—The predominating type of lava 
in this series is a basalt with large tabular phenocrysts of plagioclase, which closely 
resembles the well-known Carnethy “porphyry” of the Pentland Hills.* We shall 
refer to it as the Crawton type of basalt. The most southerly exposure of the Crawton 
basalts is seen on the shore about a mile south of Gourdon, where they are striking 
seawards in a north-west and south-east direction. Swinging round somewhat abruptly 
near Nether Knox, they return to the north-north-east and south-south-west direction 
of strike—the general strike of the synclinal fold. They may be followed along the 
higher slopes of Gourdon Hill, and ultimately crop out in the Water of Bervie near 
Pitearry Mills. There they are truncated by a fault, the line of which is marked by a 
thick fault breccia forming a prominent wall-like feature on the left bank of the river. 
Reappearing on the north side of the above fault near Mill of Bervie, the Crawton 
basalts form the lower of the two prominent rock features of Bervie Brow. As they 
are followed northwards it is found that, just west of Grange and again a short distance 
east of Wardend, the continuity of their outcrop is interrupted by two faults, which 
have the effect of shifting it successively further to the east. Good exposures of the 
basalts are seen in the old quarries in Whistleberry Wood, and the group may be 
followed in a northerly direction for about a mile and a half until it is again traversed 
by a dislocation—the Braidon Bay fault—which shifts the outcrop out to sea on the 
downthrow side. The direction of strike, however, again changes as the beds begin to 
* Mem. Geol. Survey, “The Neighbourhood of Edinburgh,” p. 32, 1910. 
TRANS. ROY. SOC. EDIN., VOL. XLVIII. PART IV. (NO. 34). 139 
