REV. E. HILL ON THE ROCKS OF GUERNSEY, 407 
The finer and more contorted seams have so sharp a line of boundary 
that the suggestion may possibly be true so far as they are concerned. 
But others, those with the coarser pockets, pass so insensibly into the 
eneiss that I cannot accept this explanation for them. I believe 
these to be contemporary with the gneiss which surrounds them, and 
sedimentary like it. If so they have been subjected during the same 
ages to the same agencies of metamorphism. And if so, we have a 
strong argument in support of the opinion that the peculiar character 
of the coarser gneisses is due, not so much to the metamorphosing 
agencies they have experienced as to the peculiarity of their original 
constituents. It is rather strange, however, that I have not been 
able to find similar beds at any other point of their line of strike. 
It is difficult to investigate the neighbourhood completely. The 
tide-swept Sound of Lihou, the storm-beaten precipices of Pleinmont, 
do not lend themselves readily to examination. I have not yet 
been able to establish any order of superposition for the beds of the 
Guernsey gneiss. I hope to resume the investigation in a future 
visit, or perhaps some resident will attack the problem. 
3. [ne DrorirEs AND SYENITES. 
The gneiss occupies, as we have seen, one half the length and 
fully three fourths of the area of Guernsey. The rocks I proceed to 
describe are found over the greater part of the remainder. 
They have been described as metamorphic; I believe them to be 
igneous, upon the following grounds :—First, though largely quarried 
over all the area in all sorts of places, not one quarry of all the 
scores I have entered shows any clear bedded structure. One or two 
show a faint streaking of colour, neither conspicuous nor extensive. 
They disclose universally broad and deep masses of uniform rock 
varied only by an occasional dyke. ‘There are no proofs of sedi- 
mentary origin. Secondly, these rocks are exposed in many outcrops 
on the shore. If any difference of texture existed, it would be 
certain to manifest itself on the coast. I have examined nearly 
every outcrop and many of them minutely. There generally is no 
indication of dip, no sign of stratification. When occasionally there 
is some appearance of banding, it is usually contradicted a few 
yards off by similar but entirely inconsistent phenomena. Two 
marked exceptions to this statement will be discussed a little further 
on. Thirdly, the distribution of the different varieties of the group 
bears no resemblance to a succession in members of a stratified 
series. If such a series were rendered crystalline by metamorphosis, 
though in any one quarry the material might be undistinguishable 
from an igneous rock, yet traced over a large area the differences in 
the original strata ought to disclose themselves as different varieties 
occupying bands of country or succeeding each other in some 
assignable order. I can detect nothing like this. There are several 
kinds of these syenites and diorites, but most irregularly arranged. 
Rocks very similar occur at widely distant points, as for instance at 
