330 Correspondence.—Prof. T. G. Bonney. 
for it a Pre-Cambrian age (Grox. Mac. p. 163)—thus admitting an 
error. Could Mr. Davies see my specimens, or the rock in the field, 
I am convinced he would have no doubt that at any rate the bulk of 
the mass is gneiss. 
2. Dr. Hicks asserted that the “newer series” in Glen Laggan 
(left bank) was not: metamorphic. I replied that though in a very 
different condition from the older series, these rocks were much more 
altered than is usual with Paleozoic deposits, and were rightly termed 
metamorphic. The real point at issue does not appear to me to have 
been made quite clear to Mr. Davies; so, with all respect for his 
opinion, I must adhere to my statement, supported as it is by good 
petrologists to whom I have exhibited the specimens and slides. 
3. Dr. Hicks asserted that the older series re-appeared in Glen 
Docherty, and so passed up into Ben Fyn and the mountain group 
southwards. I stated that of this re-appearance (in itself so improb- 
able) there was no stratigraphical or petrological evidence, and 
that the microcsopic structure of these rocks in Glen Docherty 
came much nearer to that of the newer series in Glen Laggan than 
to any other. Here again I think the evidence has not been fully 
before Mr. Davies. 
The last two points were the foundations of Dr. Hicks’s argument, 
so we need not occupy time by discussing the rocks of Ben Fyn. 
I will venture upon two further remarks. One, that it is singular 
what importance the rocks of Gaerloch have assumed in the in- 
terval between Dr. Hicks’s first and second paper. In the one they 
are dismissed merely with a vague allusion, so that I did not think 
it needful to visit a locality which seemed to have no material bear- 
ing on the controversy. Now they are placed in the forefront of the 
battle. A comparison also of the sections in the two papers (Q.J.G.S. 
vol. xxxiv. pp. 812, 814, with Groxz. Mac. p. 159) will show that 
important changes, not of detail only, have been introduced (for one 
at least of which I should like to see the evidence), These changes 
ought to have been more carefully pointed out to the reader than 
they have been. The other remark is that Dr. Hicks alludes to my - 
work as-hurried. For that accusation I venture to say there is no 
other foundation than that I did not remain in the district so long as 
himself. This, indeed, is true; but to test a theory ought not to require 
so long a time as to invent it. At any rate I remained long enough 
to convince me that the above three assertions of Dr. Hicks could 
not be established. On that point no amount of delay would have 
altered my opinion. Further, to the work in the field, the study of 
about forty microscopic slides, from most carefully selected specimens, 
has been added. As it seems to me, the author who first makes a 
rock intrusive in Silurian beds,! and then (without again visiting the 
locality, be it noted) regards it as Pre-Cambrian (cf. Q.J.G.S. vol. 
xxxiv. p. 814 with Grou. Mac. 1880, p. 159) is more open to the 
charge of hasty work. T. G. Bonney. 
' In using the term admitted by Dr. Hicks, I do not wish to commit myself to any 
opinion as to the age of the ‘‘ newer series.’” It is possible that there may be very 
much Pre-Cambrian rock in the Scotch Highlands : my contention is that Dr. Hicks’s 
proof of this is erroneous. 
