consciously or unconsciously, to hinder.


FOOTNOTES

(1) The Nineteenth Century.

(2) [Earlier, if more recent announcements are correct.]

(3) It may be objected that I have not put the case fairly
inasmuch as the solitary insect's wing which was discovered
twelve months ago in Silurian rocks, and which is, at present,
the sole evidence of insects older than the Devonian epoch, came
from strata of Middle Silurian age, and is therefore older than
the scorpions which, within the last two years, have been found
in Upper Silurian strata in Sweden, Britain, and the United
States. But no one who comprehends the nature of the evidence
afforded by fossil remains would venture to say that the non-
discovery of scorpions in the Middle Silurian strata, up to this
time, affords any more ground for supposing that they did not
exist, than the non-discovery of flying insects in the Upper
Silurian strata, up to this time, throws any doubt on the
certainty that they existed, which is derived from the
occurrence of the wing in the Middle Silurian. In fact, I have
stretched a point in admitting that these fossils afford a
colourable pretext for the assumption that the land and air-
population were of contemporaneous origin.