128 NEOZOIC TIME. [CHAP. VIII. 



close to its shore, just as the Maritime Alps border the 

 shores of the Biviera. It seems, indeed, as if the condi- 

 tions under which the lower breccias and pebbly sand- 

 stones of Devonshire were accumulated, must have been 

 very similar to those which have long existed in the Riviera. 

 Sir Charles Lyell describes some remarkable deposits near 

 Nice ; l there torrents from the Alps bring down vast 

 quantities of detritus, fine in summer, coarse in winter, 

 and this is poured into the Mediterranean, and deposited 

 in slanting layers immediately outside the mouths of the 

 torrents, the shore being so steep that depths of 2,000 and 

 3,000 feet are found within half a mile of the beach. An 

 elevated delta of this kind can be studied in the valley of 

 the Magnan (near Nice), where inclined beds of sand, marl, 

 gravel, and conglomerate succeed one another in cliffs 200 

 to 600 feet high for a distance of nine miles ; if their in- 

 clination were assumed to be a dip, this would give a thick- 

 ness of many thousand feet, whereas their real thickness 

 cannot be proved to be even one thousand. 



Similar accumulations are probably frequent where the 

 conditions are similar, and the aspect of the coarse sand- 

 stones of Teignmouth and Dawlish, with their angular 

 fragments of local rocks, seem to be torrential deposits of 

 this kind. The overlying marls may indicate submergence, 

 or a rise in the level of the water from increased rainfall, 

 which carried the coast-line farther west, and so allowed 

 a finer sediment to rest upon the coarse shore-beds. 



Whether the northern areas were at this time lake- 

 basins, or low-lying terrestrial surfaces on to which mate- 

 rial was swept by mountain torrents, is very uncertain. 

 Professor Ramsay suggests a lacustrine origin for the 

 whole of the British Trias, but Professor Bonney remarks 2 

 that " the number and size of the pebbles (in the Bunter) 



1 " Students' Elements of Geology," fourth edition, 1885, p. 20. 



2 " Geol. Mag.," Dec. 2, vol. vii. p. 407. 



