368 STRATIGRAPHICAL GEOLOGY 



over the Sid at Sidmoutli. Above* this are pale-red and grey 

 sandstones with seams of marl, succeeded by alternating bands of 

 sandstone and marl, the beds in which sandstones predominate 

 being about 75 feet thick. 



The succeeding beds are red marls with thin sandstones in the 

 lower 150 feet, but passing up into massive marls with a coii- 

 choidal fracture containing strings of gypsum and pseudomorphs 

 of rock-salt. These form the lower part of the cliffs as far as 

 Branscombe mouth, but near Beer Head a syncline carries them 

 below the beach. Higher beds occur in the Axmouth and 

 Bindon cliffs, where they finally pass up into the Rhtetic Beds. 



6. Scotland 



Rocks of Triassic age occur in several parts of Scotland, but, 

 though they resemble the English Trias in consisting largely of red 

 sandstones and marls, their stratigraphical arrangement is different, 

 and this area has therefore been left till the last. The possibility 

 that the Bunter is represented in Arran has been mentioned on 

 p. 361, but in the more northern districts it is probable that all the 

 beds are of Keuper age. 



Arran. The beds described on p. 361 are succeeded by red 

 sandstones, and these are overlain by red shales and marls. More- 

 over, recent exploration of the agglomerates which fill up the vent 

 of a huge Tertiary volcano in the central part of the island has led 

 to the discovery of large masses of rock which show a sequence 

 from red marl through Rhaetic shales into Lower Lias, thus proving 

 the red marls to be of Keuper age, and to have been succeeded by 

 Rluetic and Liassic Beds, though all other traces of these beds have 

 been destroyed by erosive agencies during Tertiary times. 15 



Western Coast. Small patches of Trias occur at the base 

 of the Neozoic rocks in Morvern and Ardnamurchan (Argyleshire), 

 in the Isles of Skye and Raasay, and on the coast of Gruinard Bay 

 in Ross-shire. They have been described by Professor Judd, who 

 remarks that the materials forming the breccias, conglomerates, 

 and coarser sandstones have evidently been derived from the older 

 rocks on which these strata repose, usually either the Torridon 

 sandstone or some member of the Highland gneissic series. 



A special feature in these Triassic rocks is the abundance 

 of calcareous matter which enters into their composition ; frag- 

 ments of compact limestone (? Durness limestone) abound in the 

 coarser beds ; the sandstones often pass into calcareous grits, and 

 bands of cornstone are not unfrequent, while all the beds are 

 frequently traversed by veins of calcspar. As a rule, breccias and 



