14 Roberts—Pre- Cambrian Rocks. 
certainly cannot be said that in either of these distinct departments 
of research,—studies whose materials appear to be as far removed 
from our use as are the ‘data’ derived from the hypotheses they have 
given birth to, from the geological laws which we at present accept, 
we have made any progress which can be termed ‘rapid,’ towards 
giving them a permanent place in the scheme of geological time. 
But there lies upon the nearest confines of the more immediately 
terrestrial study, a certain kingdom of research into which some few 
honest and earnest workers have been of late casting lines of scien- 
tific enquiry. And as this study, which yp to a very recent date 
might have been designated as one quite outside the domains of 
paleontology, does not require the aid either of a balloon, or a diving- 
bell, or a chain and windlass of unknown length and power, but may 
be entered upon with the ordinary appliances of a geological observer, 
to wit, certain tools of the smithery, good eyes, and a patient temper, 
I may, probably, be allowed to popularize somewhat the position of 
the rock-material necessary to it. 
Once upon a time, all granite-rocks were considered to be of the 
same pre-anything age. ‘That idea, of course, is exploded now; but 
I believe that I may really say that (saving the simple acknowledg- 
ment put forth in our latest manuals, that ‘granite may be of any 
age’) the alteration in high geological quarters respecting the age 
and condition of. other rocks, allied in the old text-books with 
granite, such as syenites, hornblendic schists, tourmaline-bearing 
felspars, and felspathic rocks generally, is as yet either unknown, or 
at least not so known that it may be turned to scientific and useful 
account by the majority of our field-working geologists—the source, 
in so many instances, of new and valuable lines of geological en- 
quiry. When, last year, and again in the July of the present one, I 
examined a large series of rock-specimens obtained from the cuttings 
on the line of the Mid-Scottish Railway (from Perth to Inverness), 
I was greatly struck with the petrological value of the series of 
specimens of gneissic and other metamorphosed rocks so exposed. 
The specimens which I obtained comprised some of rocks previously 
unknown in Britain. Probably the best term to designate them by 
would be tourmaline-bearing felspars, with a tendency to become 
eneissoid. But it is difficult to express by any term, however com- 
plex, the aspect of a rock which, in a single hand-specimen, exhi- 
bited thirteen different minerals. As far as I know, no rock has 
been found presenting any natural alliance with them nearer than 
Norway and Finland on the east and Canada on the west. But 
these natural equivalents, in position and mineralogical character, 
are very valuable to us as indicative of relationships. And when, 
as the question broadens, the so-called syenites of the Malverns 
claim, through the investigations of Dr. Holl, a place in the scheme 
which Iam about to draw for the pre-Cambrian age, and also the 
rocks, so irregularly presented, of Charnwood forest ask for re- 
cognition, I think I may reasonably draw the attention of those 
geologists, more happily situated than myself for purposes of investi- 
gation, to the question, How much of life-bearing time can be con- 
