Vol. 6 3 .] 



INLIER 1ST THE EASTERN MENDIPS. 



229 



ashy particles, through which are scattered well-rounded pebbles 

 of trap ranging up to a length of 6 inches. West of the quarry 

 in coarse ashy conglomerate, no exposures of the rock in situ are 

 met with, until the targets on Beacon Hill are reached ; but, along 

 the northern part of the new north-and-south fence connecting the 

 Roman Eoad between Wells and Frome with the Beacon-Farm 

 road, and at the eastern corner of the plantation north-east of 

 Beacon Farm, much tuff is mingled with the trap thrown out by 

 rabbits. It is extremely probable that this mingling of trap and 

 tuff is due to the material being derived from the weathering of 

 the coarse ashy conglomerate, the matrix of which would yield the 

 tuff-fragments, while the blocks would yield, the trap-fragments. 

 This area is shown as coarse ashy conglomerate in the map (fig. 1, 

 p. 220). 



As already mentioned, the coarse ashy conglomerate is seen in the 

 small excavation south of Beacon Plantation, made for the pur- 

 pose of erecting the targets of a rifle-range. The rock here closely 



resembles that seen in 

 Fig. 5. — Hough plan of the trenches dug 



near the Rifle -Butts, Beacon Hill, 



on the scale of 100 feet to the inch. 



(Orientation north and south.) 



Beacon plantation. 



[-iTrench in 



Old. Red Sandstone 



Fence 



Trenches in coarse 

 ashy conglomerate 



Rifle-butts 

 enclosure" 



Target-pit- 



the eastern part of the 

 district, consisting of a 

 pale-green or grey matrix 

 of fine tuff, enclosing 

 large numbers of well- 

 rounded blocks of trap 

 reaching a length of as 

 much as 6 inches. Asso- 

 ciated with the trap- 

 blocks are a small num- 

 ber of grit-blocks. Old 

 Red Sandstone is ex- 

 posed on the slopes be- 

 low Beacon Plantation 

 only 50 to 60 yards north 

 of the targets, and it 

 was hoped, by sinking 

 trenches in the inter- 

 vening tract, to ascertain 

 the relation of the coarse 

 ashy conglomerate to 

 the Old Red Sandstone. 

 Three trenches were 

 sunk, practically cover- 

 ing the whole stretch 

 between the targets and 

 the slope of the hill. All 

 proved to be in coarse 

 ashy conglomerate similar to that exposed at the targets ; but the 

 northernmost one, sunk immediately adjacent to the fence at the 

 foot of the slope, showed a greater proportion of fine tuff and a 

 smaller proportion of the large rounded blocks. A fourth trench 



Trench in coarse 

 .---''ashy conglomerate 



