Roberts—Pre- Cumbrian Rocks. 15 
ceded to eras beyond the ‘ Cambrian’?* The question is not now 
whether any evidences of life have been found, because that has been 
already most satisfactorily settled by Sir W. BE. Logan; nor yet does 
it depend on any boundary arbitrarily fixed between the Lower 
Silurian, Cambrian, or Huronian; it is rather a question of the 
extension of those or cf other forms of ‘ Fundamental Gneiss’ or 
‘Laurentian’ life. For it cannot be supposed that the gigantic 
foraminifers of the Canadian Loganite-rock will long stand alone in 
the catalogue of what, as yet, may be termed primeval life. 
Let our primitive mountain-chains be examined minutely for 
their contained layers of altered limestone or serpentine, for I am 
convinced that rocks of such characters are to be met with in many 
hitherto unsearched parts of Britain, and who shall say that life- 
relics may not be obtained from them? Markings which to the 
unassisted eye appear but as blotches and stains, may be, by micro- 
scopical aid, resolved into evidences of life more ancient than any 
yet detected in Britain. Sir R. I. Murchison, whose sagacity led 
him to place the fundamental gneissic and other rocks of the Western 
Isles beneath all life-bearing rocks in Britain, kas opened out a new 
kingdom of research; and the note of pilotage which has been 
sounded from the probably still more ancient kingdom of Laurentia 
has an assuring sound, telling us that, though unseen rocks may lie 
in the way of our ventures into the unknown sea, they are those 
which will aid us in our search, and probably reward us with the 
objects for which we seek. I would suggest, therefore, to those spe- 
cially interested in Paleozoic geology, that it would add greatly to 
the success of the enterprise, if the subject were noticed monthly in 
the GEOLOGICAL MAGAZINE by contributions, however small, from 
those who are able by proximity to mountain-chains of undoubted 
or suspected ‘Cambrian’ or pre-Cambrian age, to search narrowly 
into the mineralogical character of the rocks composing them. Such 
notes should also contain the petrology of the hills thus studied, 
and, when possible, chemical analyses of the rocks, carried out on 
the plan adopted by the Rev. Mr. Timins, in his analyses of the Mal- 
vern syenites, in which range Dr. Holl has obtained clear evidence 
of stratal deposition. We greatly need in England the labours of 
men like my venerable friend Dr. Nils Nordenskidld, of Frugard, 
who, with the aid of his son, Prof. Adolph Nordenskiéld, of Stock- 
holm, has chemically and mineralogically analysed almost every 
Finnish and Scandinavian rock, a nearly complete series of which 
I had lately the pleasure of receiving from him. Such labours 
cannot be too highly appreciated by paleontologists, for chemically 
altered paleeozoic rocks are very suggestive of fossils. Perhaps it is 
not too much to say that Sir W. Logan’s discoveries have quite dis- 
posed of the term ‘ Azoic,’ as applied to any rocks, save those erupted 
beyond all question from volcanic sources. 
In conclusion, it may be well to offer for the refreshment of our 
* Tuse the term ‘ Cambrian’ in designation of certain pre-Silurian rocks de- 
scribed by our English Nestor, Professor Sedgwick, and to which may be referred 
the ‘ Primordial zone’ of the Paradoxides-bearing rocks of St. Dayid’s. 
