117 
the Radstock coal basin,” read before this club, and published in 
the first Volume of Proceedings. 
Reverting to the teaching of science on the origin and action of 
igneous rocks, and the apparent evidence in the mines and on the 
surface of the Bristol and Radstock coal basin ; there can be but 
one opinion of the connection of the dyke and those disturbances. 
As to the nature of that connection the example on Mendip affords 
us more than ordinary facilities for studying. One of the dykes, 
or, perhaps, more correctly a part of the dyke (a point which we 
shall hereafter consider), is now being quarried for road metal and 
very much opened up. It is a basalt rock containing less than 60 
al 
advantage of avery able and interesting paper on “The faults of 
per cent. of silica, much iron and interstitial copper. One 
remarkable feature is frequently seen proving its original 
semi-fluid condition ; where one plastic mass has been pushed past 
another in its upward course, a slimy surface is seen similar to 
the marks produced when a rough surface is drawn over thin 
plaster. The dyke extends in nearly a straight line from Beacon 
Hill to Downhead, a distance of three miles, occupying the centre 
of the anticlinal. There is undoubtedly a very close connection 
between this, and the great Clandown fault which intersects the 
Mendips, near their eastern extremity. Striking into the centre of 
the basin at Timsbury, this fault passes between the Newbury and 
Mackintosh pits where the downthrow west is 750 feet, leaving 
the Kilmersdon pit alittle to the west, with a downthrow west of 
384 feet ; from thence it passes on between Ludlows and Middle 
pits, Radstock, the downthrow being 606 feet, and still increasing 
to 720 feet at Clandown the centre of the basin. From this point 
the downthrow west decreases to 120 feet. At Lower Conygre 
pit, Timsbury, the fault comes to a termination, by connection at 
nearly right angles with Clutton Union fault. Putting it in 
nore simple terms; the basin has split into two parts through 
the centre and the western side has gone down below the other 
the amount given (750 feet). 
