806 REPORT—1896. 
the aspect of a boulder clay with bedding inclined tothe east. Every layer, in the 
thickness exposed of 14 feet, is full of fragments of yellow sandstone, all apparently 
derived from one deposit, such as the Ashdown sand. They are all angular, and 
vary in size from one inch to two feet in length. There is no trace of smoothing or 
grooving on any of the large number of fragments examined, and therefore no 
ground for attributing their transport to ice. The volume of water which 
would effect transport of such a thickness of clay may have been merely the 
result of exceptionally heavy rain, for the large fragments appear to be torn away 
by their natural joints and bedding planes, and the small fragments are such as the 
action of varying temperature would produce in a terrestrial surface. The angle 
of dip was about 15°. Mr, F. G. Smart, M.A., F.L.S., of Tunbridge Wells, photo- 
graphed the sections at the author's request. 
It is remarked that, although alternating green and red clays in geological 
deposits are generally of freshwater origin, there is a similar alternation in some 
of the old Cambrian slates. 
8. On some Crush-Conglomerates in Anglesey. 
By Sir Arcuipatp Geixiz, PS. 
The important observations made by Mr. Lamplugh among the ‘ crush- 
conglomerates’ of the Isle of Man suggest that the phenomena described by him 
may have a much wider range than had previously been supposed. Ever since the 
author had the opportunity of going over the Manx evidence with him, he has sus- 
pected that some of the fragmental rocks which he has himself regarded as volcanic 
agglomerates might prove to be due, not to volcanic explosions, but to the same 
kind of underground movements which have undoubtedly given rise to the enor- 
mous masses of ‘ crush-conglomerate ’ in the Isle of Man. The breccias of Anglesey 
seemed to the author likely, on renewed examination, to prove to belong to the 
latter series. Accordingly he recently took occasion to revisit these rocks, both in 
the centre and along the north coast of the island. The result was entirely con- 
firmatory of his suspicions. The breccias in question are, he now feels convinced, 
true crush conglomerates. 
The amount of mechanical deformation which these rocks have undergone is 
one of their most obvious characteristics. On the supposition of their volcanic 
origin, it was quite conceivable that coarse agglomerates and volcanic breccias 
might undergo crushing together with the sedimentary series to which they 
belonged, so that the evidence of deformation formed is itself no proof that they 
were not of pyroclastic derivation. But more detailed investigation, in the light 
of the Manx examples, bringsto view proofs that the conglomeratic structure has been 
produced by the breaking up of stratified rocks zz situ, At Llangefni, for example, 
the strata affected appear to have been originally shales or mudstones (with possibly 
some fine felsitic tutis), alternating with bands of hard siliceous grit. They have 
been crumpled up and crushed into fragments, which have been driven past each 
other along the planes of movement. Every stage may be traced, from a long piece 
of one of the grit-bands down to mere rounded and isolated pebbles of the same 
material. The grits, being much more resisting, have withstood the deformation 
better than the argillaceous strata, which have been crushed into a kind of broken 
slate or phyllite. Kyerywhere the signs of movement, or ‘flow-structure,’ meet 
the eye. It is not that the rocks have been merely crushed to fragments; the 
differential movements which produced the ruptures also made the materials to 
flow onwards, the dislocated bands of grit being reduced to separate blocks and 
pebbles entirely surrounded in the moving matrix of finer shaly paste. 
The ‘agglomerates’ on the coast near Cemmaes, so singularly deceptive as to 
be easily mistaken for volcanic necks, prove to be capable of a like interpretation. 
The huge blocks of limestone there to be seen, isolated among fragmentary grits 
and slates, are referable to the disruption of some of the limestone bands which 
occur abundantly in the neighbourhood. A gradation may be traced from the 
slates and grits outside the areas of more severe dislocation into the intensely 
crushed and sheared ‘agglomerate.’ The dykes which cut through these rocks 
