RASTALL : THE INGLETONIAN SERIES OF W. YORKSHIRE. 95 
to give any intelligible description of the macroscopic appearance 
of this rock, since it varies a good deal in character. The greater 
part of it is a coarse grit or conglomerate, consisting of crystals 
of quartz and felspar, both red and white, with abundant rock 
fragments of very variable size, and much chlorite. These 
constituents produce a very distinctive rock-type, having a 
peculiar mottled appearance and showing green, white, and 
red colours. There are also abundant veins of both quartz and 
calcite, the latter often of a pink colour. Mixed up with coarse 
grit there are in most parts of the mass abundant angular and 
subangular fragments of a fine-textured rock of a dark green 
colour, showing very little structure. It has been suggested 
that this rock is as a whole of kataklastic origin, in fact a crush- 
breccia, and certainly its naked-eye appearance does favour 
this view. But the microscopic evidence is inconsistent with 
this hypothesis : although the rock has undoubtedly undergone 
a considerable amount of crushing since its deposition, it is 
clearly of polygenetic origin, and the fragments are well rounded 
and waterworn. 
I have examined a large number of slices of this rock and 
the results of this examination are of interest. It consists essen- 
tially of subangular and rounded fragments of very diverse 
character. On the whole, the smaller fragments are the more 
angular, and the larger ones, which may be described as pebbles, 
are often very well rounded (see Plate VII.). There are abundant 
simple grains of quartz, felspar, and other minerals, such as 
have already been described in the case of the finer grits, but 
of more importance are the compound grains or rock-fragments, 
since these are usually large enough for their petrographical 
character to be easily recognisable. They consist almost 
exclusively of igneous and metamorphic rocks, and it is clear 
that the material of this conglomerate has been derived from 
the denudation of an area of gneisses and crystalhne schists, 
together with igneous rocks of both intrusive and volcanic 
types. 
Among the metamorphic rocks, perhaps the most con- 
spicuous are well-rounded fragments of quartzite of various 
degrees of fineness, and most of them show very clearly the 
