316 



ME. 0. A. SHKUBSOLE ON TRIASSIC PEBBLES OF [Aug. I9O3, 



over each other with a grinding noise. The result is to produce a 

 new deposit altogether, in which the pebbles are usually of a totally 



different shape. They now 

 become as a rule symme- 

 trical, and lose all trace of 

 angularity. 



The Pebble-Bed, therefore, 

 must be examined in inland 

 sections. There are exten- 

 sive gravel -pits between 

 Budleigh Salterton and Ex- 

 mouth, in which the pebbles 

 are worked for road-metal. 

 In other parts of England 

 where flint and other hard 

 materials are abundant, the 

 Triassic pebbles are usually 

 regarded as an undesirable 

 element, from the difficulty 

 of breaking them up. Here, 

 however, they form the sole 

 material readily available 

 for mending the roads ; and 

 the men who are employed 

 in breaking up the stones 

 are of a fine muscular type, 

 bringing to the work not 

 only strength, but skill, 

 for they have acquired the 

 knack of knowing the best 

 way of attacking a stone 

 with success, so as not to 

 waste their blows. They 

 informed me, however, that 

 the larger pebbles cannot be 

 broken up without a sledge- 

 hammer. 



It may be well also to 

 state that much of the 

 ground in this district is 

 covered by Drift which con- 

 tains a large proportion (90 

 per cent.) of the pebbles. 



With regard to the rock- 

 material of which the pebbles 

 are composed, I cannot add 

 anything to Prof. Bonney's 

 description. 1 Its general character is, of course, the preponderance 

 of quartzites of varying texture and colour, often of some shade of 

 1 Geol. Mag. 1895, p. 75. 



