90 
Wrington, and turning an angle, the two sides close in and 
become more precipitous, forming, perhaps, the finest part of the 
whole. Still farther on where the Combe branches off to the 
the right and left, immediately at the point of bifurcation, the 
secretary pointed out an exposure of Trap rock ; but reserved his 
remarks thereon until the Members had reached the head of the 
Combe under Broadfield House. The party increased by several 
visitors, and by the presence of the Vice-President of the club, 
who had joined them during the morning’s walk, were not 
disinclined to rest for a space near a section of the Old Red 
sandstone, whilst the Secretary took advantage of this, and with 
the geological map fastened to the stem of an oak tree delivered 
himself of a few notes on the geology of the district. 
Having recapitulated what he had stated last year as to their having 
crossed to the western edge of the Bristol Coal basin, and that Broadfield 
Down, an isolated mass of Carboniferous Limestone, was one of the western 
boundaries of this basin; he spoke of the exposure of Trap which the 
Members had passed over in the morning. The question naturally arose, 
was it intrusive? i.e., had the igneous rock been injected into a fissure of 
the Limestone ; or was it interbedded ? i.¢., had the fused mass originally 
burst forth and spread over the surface, and been subsequently covered 
over by more recent deposits? From the appearance of the Limestone 
rock, a specimen of which he held in his hand, the Secretary considered it 
was intrusive, and had altered the strata into which it had originally been 
injected. In this case the Trap was of subsequent date to the Limestone, 
and could not have been the cause of the disturbed character of the beds 
in its vicinity, but had been poured forth into the joints and fissures caused 
by the same disturbing force which had produced the anticlinal folds of 
Broadfield Down and the Mendip Hills. The similarity of the structure 
of the two was then touched upon. On a former occasion (vide Vol. IL, 
No. 4, p. 485) he had stated that the Old Red Sandstone beds were un- 
exposed on Broadfield Down. Since then and during a walk with one of 
the members of the Club in search of a second exposure of Trap farther up 
the Combe, he had found that section of Old Red near which they were 
sitting ; it however was laid down on Mr. Saunders map, a copy of which 
he had not previously seen. This, then, evidently formed the nucleus of 
Broadfield Down, as it did of the Mendips; the Mountain Limestone 
