320 ON THE ANCIENT GRAUWACKE 
for the accomplishment of any other. In the various notices 
of our Scotch Grauwacke which cccur in the Transactions of 
the Edinburgh scientific societies during the years in which 
the battle raged between the two schools, I do not find trace 
of a single discovery worthy of being introduced into a his- 
tory of the system. Curious observers, however, outside the 
area of the conflict, seem to have been now and then finding 
in the deposit occasional traces of the organic. I have been 
told by the late Mr. William Laidlaw (the trusted friend of 
Sir Walter Scott), whose acquaintance I had the pleasure of 
forming early in 1839, that on two several occasions, many 
years before, he had found minute bivalves, and what he 
deemed vegetable impressions, in the Grauwacke slates of 
Peebleshire. 
The second notice of fossils in our Grauwacke at all defi- 
nite in its details, and which intimated original discovery, oc- 
curred long after the first, — at a time when geology had made 
rapid strides towards the position which it at present occu- 
pies, — and was of a peculiar interest to Edinburgh geologists, 
from the near neighborhood of the locality which it indicated 
to the Scottish metropolis. In 1839, Mr. Charles Macklaren 
published his “ Geology of Fife and the Lothians;” and in 
that ingenious work,— equally remarkable for the boldness 
of its theories and the truthfulness of its observation, — geo- 
logists were first told that there exist fossils in the Grau- 
wacke slate of the Pentlands. The organisms of the older 
rocks are not unfrequently restricted to a single stratum: 
even in the Lower Old Red Sandstone one may pass along 
sections of the strata many hundred feet in thickness, with- 
out detecting a trace of aught organic, and then find in some 
thin layer, perhaps not a foot in thickness, the fucoids, or 
fishes, or minute bivalves, of the formation, congregated by 
hundreds and thousands; and in the Scotch Grauwacke this 
