Vol. 69.] VOLCANIC ROCKS OF THE FORFARSHIRE COAST. 467 



All the accessible rocks appear to be olivine -basalts, the type 

 with felspar-phenocrysts disappearing westwards. The outcrop 

 of the lavas terminates as a cliff, against which Glacial deposits, 

 beaches above the present level, and blown sand are banked up. 

 I could find no evidence of the relations between the lavas and 

 any other solid rocks in the vicinity. 



(b) Lunan Bay to the Red Head. 



From Lunan Bay to the lied Head, all the volcanic rocks are 

 olivine -basalts, between which, with one exception, it is not 

 easy to distinguish in the field. The exceptional type has obvious 

 felspar-phenocrysts, and is exposed in the lower part of the cliff 

 for about 300 yards west of Ethie Haven. No dykes have been 

 found in this series. 



There seems to be no doubt that a considerable thickness of 

 sandstone — Dr. Hiekling's Cairnconnan Series l — is intercalated 

 between the lavas on the south and those on the north of Lunan 

 Bay. For some distance west of Lunan Baj' the solid rocks are 

 buried under superficial deposits, but in the south-western corner 

 of the bay several outcrops of sandstone of a different kind occur 

 in the cliff and on the beach. 



Near the base of the cliffs at Bird's Knap, immediately south 

 of the mouth of Keilor Burn, is an exposure, almost obscured by 

 vegetation, of red and yellow sandstone resting upon a breccia 

 containing angular red sandstone. Black Bock, which emerges 

 from the sand on the shore about 100 yards north-east of this 

 exposure, is a mass of breccia, composed almost entirely of angular 

 red sandstone, but containing a few small rounded boulders of 

 volcanic rock. South-eastwards, the sand on the shore gives place 

 to a bare rock-surface consisting of much-weathered volcanic rock, 

 which rises here and there into stacks of harder but still much- 

 weathered basalt. No sandstone appears, except the usual sedi- 

 ment intercalated with the lavas. South-east of Bird's Knap 

 the cliff rises, but continues to be grassed over until it bends 

 sharply eastwards, where it is seen to consist entirely of basalt. 

 The lower part of the cliff is well-slicken sided for some distance, 

 and clearly indicates the presence of a fault ; this appears in a 

 projection of the cliff farther west, and eastwards runs across the 

 beach. The fault has a trend about 15° north of east, hades 

 northwards at an angle of 1 ( J°, and the slickensides incline west- 

 wards at an angle of 20° from the vertical. There is a good deal 

 of smashing parallel to this fault, which is marked by parallel 

 veins of calcite wherever a section occurs in a direction at right 

 angles to the cliff. It is quite clear that the trend of the cliff is 

 largely dependent upon the direction of this system of faults. 



About 200 yards east of the south-western corner of Lunan Bay, 

 a mass of silicified fault-breccia (3 feet wide) stands out like a 



1 Geol. Mag. dec. 5, vol. v (1908) p. 4C0. 



