the
fields. The mention of these facts may be of service to those who have
had opportunities for observation elsewhere.

The Society have also had their attention called to disturbances of
another sort--earthquakes; of which not a few have occurred of late in
many parts of the world, our own island among them. The shocks appear
to have been most severely felt in the south-west--Cornwall, for
instance, and the neighbourhood of Bristol, where they extended over
an area of more than thirty miles. The effects have now been
accurately described: one of the shocks lasted two seconds; the other,
from ten to twelve seconds, accompanied by a rumbling noise. The line
of disturbance was from north to south, striking the Mendips, and
traversing parts of the shires of Somerset and Gloucester. 'The chief
focus of oscillation was at Cheddar, where the hill is said to have
waved to and fro during several seconds; and in the alluvial flat or
marsh below Cheddar, some houses had the plaster of the ceilings
cracked; while in others, the clocks struck, doors slammed, bells
rung, &c.' With such commotions taking place in the solid earth,
geologists will not fail of sources of interest in their favourite
study. There is yet another geological fact worth mentioning--the
finding of footprints in what is called Potsdam sandstone, near
Montreal, in Canada. This sandstone is the 'lowest member of the
lowest Silurian rocks;' and the discovery is good evidence that there
were living creatures walking on the land at the very oldest periods
hitherto revealed by geology--thus carrying back the appearance of
organic life to a time more remote than had been supposed. Professor
Owen, who has examined the slabs and casts, says, that no idea of the
creature that made the tracks can be formed from any animal at present
existing, for instead of the prints being in successive pairs, an odd
one is found to intervene. He considers it to have had three legs on
each side, and to have been neither tortoise-like nor vertebrate; and
after naming it _Protichnites_, adds: 'I incline to adopt, as the most
probable hypothesis, that the creatures which have left their tracks
and impressions on the most ancient of known sea-shores, belonged to
an articulate and probably crustaceous genus.' The fact is an
important one in a scientific point of view, and presents a new
standpoint for inquirers.

There is advancement, too, in other quarters. Faraday has been
diligently p