380 PROFESSOR GEIKIE ON THE 
high headland of Cnoc na Croiche, and a range of sea-precipices nearly two 
miles in length. In their lower part they are highly felspathic, with a rather 
coarse texture, and many scattered pebbles, as well as nests and bands of con 
glomerate. Higher up they are more flaggy, and they finally pass upward im- 
perceptibly into the dull-red and grey flagstones of Berriedale. Nothing but an 
arbitrary line can be drawn for their upper limit; but if we place that line a 
little to the south of the mouth of the Berriedale Water, the thickness of this 
red sandstone group is found to be about 2000 feet. The group has as yet 
yielded no fossils. 
Before tracing these strata inland and westward, we may look at their pro- 
longation northward along the shore. On both sides of the Berriedale anti- 
cline they are found overlying and dipping away from the brecciated conglo- 
merate. On the north side they are particularly well seen. They have there 
already lost the coarse pebbly and conglomeratic features so conspicuous on 
Cnoc na Croiche. They become fine flaggy sandstones, with sandy shales, the 
whole having a prevailing dull chocolate-red tint, through which seams of 
greenish-grey shales and flags occur. At last, at the headland of An Dun, these 
strata become very thin-bedded and flaggy, and assume most of the ordinary 
characters of the Caithness flags, though still retaining their prevailing red 
colour. At the Sarclet anticline, further interesting evidence is supplied of the 
gradual diminution of coarse sandy sediment towards the north. The red 
sandstones are thin-bedded, and alternate with red and grey shales, and 
ereenish-grey calcareous flagstones, until they pass insensibly into the ordinary 
flagstone series. As was observed by SEDGwick and Murcuison, the red tint 
is often local and even superficial, the same stratum being red or green at 
different parts of its course. Beyond the Sarclet anticlinal axis, the red sand- 
stones and shales are prolonged, partly by the agency of faults, as far as the 
Brough, near the Castle of Old Wick, where a series of dull-red flaggy 
sandstones and shales, without thick beds, forms a large isolated stack. 
These thin-bedded rocks doubtless represent the An Dun beds just re- 
ferred to. 
While, then, the red strata become more and more mixed with fine muddy 
sediment as they advance northwards, they present very different characters as 
we trace them inland to the west. In the Langwell Water they are admirably 
displayed with the same general type as on the coast. But on the north side 
of the Scarabin ridge they so increase in the quantity of coarse detritus 
scattered through them, that for hundreds of feet in vertical depth they may 
either be called highly conglomeratic sandstones or sandy conglomerates. It 
is this coarse mass of sediment which, rising above the red sandstones and 
shales of Braemore, forms the remarkably picturesque cone of the Maiden 
Pap, the rough-topped ridge of Smean, and the huge pyramid of Morven. It 

