306 
THE GEOLOGIST. 
fig. 8, just beneath the surface of the ground, it can, however, be dis- 
tinctly seen that some change is going on, because the joint-lines 
are rather more distinctly visible and the horizontal lines mo"e 
numerous ; and here we may observe (standing on the bank of the 
lower quarry, with the eastern or upper face of the older quarry in 
view, and the prominent mass of Haytor still higher up and further 
ofi") a teaching series of appearances in the granite. In the face of 
the newest quarry we see the joints in their natural condition, almost 
unaffected by the percolation of surface-waters, and by exposure to 
weather for the last thirty or forty years ; but in one small portion 
of this face already alluded to, may be traced in outline the sectional 
areas of several flattish blocks of granite (fig. 8), of various dimen- 
Lign. 8.— Portion of Eastern Face, New Quarry, Haytor. 
sions, bounded by joint-lines, and which Avotild be in the course of 
time, if exposed to adequate agencies, separated one from the other 
by the removal of the intervening softer part of the rock, and would 
either be tumbled down by force of gravity, or would remain piled 
up more or less regTilarly one lapon another (if the destruction of 
the rock took place in the air without the intervention of the sea or 
rivers). There is one such mass, marked out by the intersection of 
oblique joints (indicated by « in fig. 8) which might possibly weather 
away into a sufiiciently symmetrical form as to remain poised on the 
underlying hump-backed mass of rock which is so bounded by joints 
as to promise to withstand the destructive action of wind and 
weather, should ever time bring about such changes of the surface 
as would lead to the modification of the Dartmoor district and expose 
it to the erosive action of air and water in those long continued pro- 
cesses which have in former times cut out and left the uprising mass 
of Haytor on the hill above (fig. 3) : — and the slow, but possibly not 
