File:The Quarterly journal of the Geological Society of London (13205744925).jpg

1847.. MURCHISON ON THE SILURIAN ROCKS OF N. WALES, ETC. 167
if'^d
y^'
wacke," which was meant to represent cer-
tain inferior urifossiliferous rocks (like those
of the Longmynd range of Shropshire). Now
on sending a copy of my new classification to
M. Elie de Beaumont, that eminent geolo-
gist, wishing to mark strata separated by
lines of dislocation by separate names, sug-
gested the propriety of further distinguish-
ing those last-mentioned unconformable and
inferior rocks by the term " Hercynian," as
taken from the Hartz mountain in Germany,
where, as he then believed, the oldest slaty
group would prove to be of higher antiquity
than the strata to which I had applied the
word " Silurian." Unwilling that the name
for these infra- Silurian rocks should be
taken from a foreign country, in which no
precise palaeozoic horizon had then been
lixed, I at once urged Professor Sedgwick
to apply to his slaty rocks, which were con-
fidently believed to be inferior to my own,
some term, on the same geographical prin-
ciple by which I had been governed in pro-
posing " Silurian/' I even ventured to sug-
gest the word " Snowdonian," because I
knew that my friend then considered the
N.W. portion of the Welsh chain to be made
up of the oldest fossiliferous masses ; but
preferring a more comprehensive geogra-
phical name, he took that of " Cambrian."
With this arrangement we both felt certain,
that no anomaly could be introduced into
the lower palaeozoic classification, as the re-
lations and fossil contents of mineral masses
which v/ere contiguous, must be eventually
cleared up without fear of error or the in-
troduction of theoretical views.
The word " Cambrian " (as far as I know)
was first used in print by myself in the year
1836, in describing the structure of Pem-
brokeshire. But whilst I then spoke gene-
rally of such Cambrian rocks, and after-
wards at greater length in my large volume,
their analysis and examination formed no
part of my scope ; that task having been
specially undertaken by Professor Sedgwick,
at a time when I really believed, that from
their great thickness, apparent inferiority
and different lithological structure, they
would be found to contain a suite of orga-