Yol. 69.] THE VOLCANIC ROCKS OF THE FORFARSHIRE COAST. 471 



they dip beneath a thick mass of very red conglomerate. This 

 ■conglomerate rests upon more than one type of basalt, and it doubt- 

 less marks a stage when the eruptions were much less frequent and 

 considerable erosion of the lavas took place. Its materials are 

 very much weathered. At least two very fine-grained basalts are 

 included within the conglomerate, one of which is well displayed 

 immediately east of Ethie Haven at high- water mark. It forms an 

 extremely-irregular lenticular sheet, and, where it thins out, appears 

 to split into two or three layers which dovetail into tbe conglomerate. 

 The upper surface of the conglomerate is irregular, sometimes 

 •dipping steeply under the lava which rests upon it. The lava is 

 fine-grained, and breaks into thin plates near the junction. 



In general appearance, the basalts met with above this horizon 

 closely resemble the lavas already described. 1 Very rugged coast 

 scenery results from the action of the waves in tunnelling through 

 the soft amjrgdaloidal lava and conglomerate and preserving the 

 .more compact lavas, although sometimes a conglomerate is more 

 resistant than the lavas. 



On the eastern side of the promontory, where the coastline leaves 

 ILunan Bay and turns abruptly southwards, is a series of amygda- 

 loidal lavas having at its base a red conglomerate. Immediately 

 above the conglomerate occurs a mass of big rounded blocks of scoria- 

 ceous lava, embedded partly in lava of a similar type and partly in 

 finer conglomerate. This is another example of ' pillow '-lava. 



Excessive weathering of the compact basalts seems to show itself 

 in the development of calcite in felspar, pyroxene, and olivine alike, 

 .giving to the whole rock a pale coloration, almost white by 

 ■contrast with the comparatively unaltered rock. Such rocks aro 

 .generally found in association with red ' conglomerates.' Fine 

 examples may be observed in the neighbourhood of the ' Spectacle.' 



South of Rock Skelly, excellent sections occur, showing a true 

 ■conglomerate, with large boulders of volcanic rock, resting upon a 

 very irregular denuded surface of the underlying lavas. Along the 

 .shore, the waves are cutting away the softer conglomerate, and 

 laying bare the hard stacks of lava buried beneath it. 



At Hock Skelly, a thick sheet of hard lava fills in and covers the 

 .hollows and mounds which form the surface of the conglomerate. 



The lower portion of this lava is very platy, the divisional planes 

 •preserving a rough parallelism with the irregular surface of the 

 •conglomerate, which is hardened at the contact and overhangs the 

 softer conglomerate beneath it in the cliff. The main mass of 

 'the lava exhibits a rude columnar jointing, and although upwards 

 of 3" feet may be seen in some sections, its original upper surface 

 •does not appear. There is little doubt, however, that the conditions 

 which produced the conglomerate beneath it continued after its 

 •extrusion, and led to its partial removal by denudation before it was 

 projected by further sedimentation. This is more likely because 



1 Ante, pp. 461, 462. 

 <i. J. G. S. No. 275. 2 i 



