Lamplugh : On Movements in Rocks. 185 
There is one further illustration of the instability of rocks 
under forceful earth-movement to which I should like to draw 
your attention, because it impressed me greatly when I was 
at work in the Isle of Man. The rocks in which the phenomena 
occurred were clay-slates with bands of hard grit or quartzite. 
These rocks have been violently pressed, crumpled, and thrown 
into all kinds of twists and folds. But the slates were able 
to adapt themselves to the movements more readily than were 
the hard grit-bands interbedded among them ; consequently 
the beds did not hold together ; disruption set in; the grit- 
bands were broken up into fragments, and squeezed among the 
slates, and a curious new rock was produced in which all trace 
of the original bedding was lost. From its superficial resem- 
blance to a clastic conglomerate, I named this rock * crush- 
conglomerate.’ Now, this crush-conglomerate is some hun- 
dreds of feet thick in places, and extends in a great sheet for 
several miles, so it may be judged what co nmotion there was in 
the rocks when it was produced. The intense squeezing not only 
broke up the beds into fragments, but also brought about a 
general re-arrangement among all the minuter particles in the 
mass, so that the slates were converted into sericitic schist. 
The crags of Sulby Glen and Gob y Deigan, in which the crush- 
conglomerate is displayed, are restful enough to look upon, but 
to me, after I had worked among them, they carried the im- 
pression of vehement turmoil. (See Plate XII, fig. c). 
It is easy to appreciate the visible effect of these great 
earth-movements, while their interstitial effect may be over- 
looked ; and it is this minute restlessness that I have sought 
to emphasize. Whether the strata as a whole are quiescent or 
whether they are undergoing disturbance, the interstitial play, 
in one form of another, is inceasing. I might have adduced 
many further illustrations of it, but perhaps those I have 
touched upon will suffice to bring to notice the activity that 
is masked by an impassive exterior in the stony framework of 
the earth. 
eee Se 
An invitation having been received from the Heckmondwike Natura- 
lists’ Society for the Annual Meeting of the Yorkshire Naturalists’ Union 
to be held at Heckmondwike in December next, the Executive Committee 
has decided to accept the invitation. The next Annual Meeting of the 
Union, therefore, will be held at Heckmondwike, and not at Dewsbury. 
‘ The capture of a couple of females by Mr. Dutton ’ seemed somewhat 
startling to read in a pamphlet before us, until we noticed that it was the 
innocent entomological notes from the Warrington Field Club, ‘ gathered 
from fugitive sources.’ We are invited to criticise, but beyond ‘pointing 
out that there are almost as many interesting records as there are mis- 
prints, we have but little to say ; bembeciformis seems particularly to have 
troubled our Warrington friends, and though they have tried spelling it in 
different ways, they have not guessed it right! We are pleased to see that 
entomology (not etymology !) is a strong feature at Warrington. 
1gtt May 1. 
