Lamplugh :. On Movements in Rocks. 181 
want to impress the idea that the deadness of the stone has 
been ‘ greatly exaggerated.’ To illustrate this, I propose to 
touch upon just a few of the symptoms of unrest that force 
themselves upon our attention in examining the rocks. It 
goes without saying that to deal thoroughly with any one of the 
forms, even supposing that such a course were within our power, 
would require more time and patience than we have at command. 
Yet I think that it will be possible quickly to dispel any remnant 
of reputation for immutability that the rocks may still have, 
by simply fixing attention on some of the lively processes that 
are constantly in operation among them. The comparatively 
simple processes affecting the sedimentary strata will provide 
us with ample matter for this purpose. 
(1) Let us first consider the processes of solidification under- 
gone by a piece of banded slate which we know was once the 
muddy sediment of a sea-floor; or by a piece of quartzite that 
was once a loose aggregation of sand-grains ; or by a fragment of 
compact limestone that was once a soft calcareous ooze. In 
our present seas all these deposits occur in their pristine state, 
and we can trace their equivalents of bygone times backward 
through all the ages and epochs to the very earliest, finding 
them as a rule, though not invariably, more and more changed 
as we go backward down the scale of geological formations. 
Mud becomes clay, then shale, then slate; sand becomes 
sand-rock—sandstone—quartzite ; calcareous ooze becomes 
porous rock—firm stone—compact limestone, though not 
always by these stages. Through the gradual loss of water, the 
creeping of particles nearer each other, the filling of interstitial 
spaces by travelling matter, under the slowly but constantly 
varying conditions of pressure and temperature, these changes 
have been going on incessantly through all the ages ; and—the 
point I want particularly to emphasize—they are going on now 
under our feet. A million years ago many of the rocks were 
not as we find them to-day ; and a million years hence they 
will again be different. 
These processes have affected and are affecting every 
particle of the solid crust, bringing about re-adjustments 
throughout the mass. Personally, I believe that some of 
the phenomena of disturbance ona visible scale that we usually 
assign to earth-movements of the more violent kind may be 
the result solely of re-adjustments made necessary by con- 
solidation-shrinkage.* (Plate XI., fig. 5). 
(2) Next let us turn to the curious processes of seggregation 
and concretion that are so frequently exemplified in the sedi- 
mentary rocks—the slow but irresistible gathering together 
* This and other points in the address were amplified and illustrated with 
the aid of specimens and lantern slides. 
1QII May * 
