222 Messrs. Hicks and Davies— 
(Mr. J. W. Salter). Tn the limestone at Ardwick, near Manchester, 
Upper Coal-measures (Phillips, Binney, Salter). In a bed thirty 
yards above the Arley Mine, Middle Coal-measures, at Bolton-le- 
Moors (Mr. J. W. Salter). These localities are in the Coal-measures 
of England and Wales. 
(To be continued in our next Number.) 
V.—On tHe Pre-Camprian Rocks oF WEST AND CENTRAL 
Ross-SHIRE. 
By Henry Hicks, M.D., F.G.S. 
Wite PertrrorocicaLt Norss. 
By T. Davizs, F.G.S., of the British Museum. 
‘ 
Parr III. 
Glen Laggan and Glen Docherty. 
HE rocks described by Mr. Davies in Notes 15-20 belong to the 
newer series, and were collected as nearly as possible at the points 
indicated in the sections. They are here described for comparison 
with the older rocks already referred to, and with the rocks to be 
further mentioned to the east of this line. I selected intentionally 
for examination those which appeared most highly altered, or other- 
wise to have any resemblance to the old rocks; as it is well 
known that Prof. Nicol considered them to belong to that series, and 
not to the newer groups. The petrological evidence as given by 
Mr. Davies proves that they are in no way allied to the gneiss 
rocks of the old formation, and that they are not sufficiently meta- 
morphosed to be allied to any schists of known Pre-Cambrian 
age in these areas. These facts, combined with the physical evidence 
of the discordance in strike also almost everywhere apparent, seem 
therefore conclusively to prove that they cannot be of Pre-Cambrian 
age, but that they belong to a much younger series, and overlie the 
limestone group found along the west side of Glen Laggan. 
Nos. 17 and 18 were collected almost immediately upon the lime- 
stone, in the line of Section III., and hence at a lower horizon in the 
succession than the others. There can be little doubt that these at 
least form a part of that group. They are flag-like in character, of 
a dark bluish tint, and sometimes of a very fine grain. They 
alternate, however, in some places, with almost pure sandstone 
bands. Near the diorite they are considerably twisted about and 
crushed. The usual dip is to the 8.H., and here at a moderately 
high angle. There is distinct evidence of considerable disturbance 
and faulting at this point. The next series, f, though not actually 
seen here to repose upon the limestone group, appear undoubtedly to 
overlie some comparatively unaltered sandstones and flags, and, I 
believe, unconformably. If these belong to the limestone series, 
then the evidence seems to show that we have a physical break at 
this point in the succession. If this is a fact, much of the diffi- 
culty experienced in unravelling the sections to the N. and 8. along 
this line is easily explained. In some it would appear as if the 
