partly petrified. This is a startling fact for natural
philosophers, and must cause them to modify the existing theory of
petrification.--_Kennedy_.

This account, at first discredited, has since been corroborated by the
discovery of a completely petrified forest, near the head waters of the
Cheyenne, or Chienne river, which has its source in the Black Hills of
the rocky chain.

There is scarcely, perhaps, a spectacle on the surface of the globe more
remarkable, either in a geological or picturesque point of view than
that presented by the petrified forest, near Cairo. The traveller,
having passed the tombs of the caliphs, just beyond the gates of the
city, proceeds to the southward, nearly at right angles to the road
across the desert to Suez, and after having travelled some ten miles up
a low barren valley, covered with sand, gravel, and sea shells, fresh as
if the tide had retired but yesterday, crosses a low range of sandhills,
which has for some distance run parallel to his path. The scene now
presented to him is beyond conception singular and desolate. A mass of
fragments of trees, all converted into stone, and when struck by his
horse's hoof ringing like cast iron, is seen to extend itself for miles
and miles around him, in the form of a decayed and prostrate forest.
The wood is of a dark brown hue, but retains its form in perfection, the
pieces being from one to fifteen feet in length, and from half a foot to
three feet in thickness, strewed so closely together, as far as the eye
can reach, that an Egyptian donkey can scarcely thread its way through
amongst them, and so natural that, were it in Scotland or Ireland, it
might pass without remark for some enormous drained bog, on which the
exhumed trees lay rotting in the sun. The roots and rudiments of the
branches are, in many cases, nearly perfect, and in some the worm-holes
eaten under the bark are readily recognizable. The most delicate of the
sap vessels, and all the finer portions of the centre of the wood, are
perfectly entire, and bear to be examined with the strongest magnifiers.
The whole are so thoroughly silicified as to scratch glass and are
capable of receiving the highest polish.-- _Asiatic Magazine_.

(*3) The Mammoth Cave of Kentucky.

(*4) In Iceland, 1783.

(*5) "During the eruption of Hecla, in 1766, clouds of this kind
produced such a degree of darkness that, at Glaumba, which is more than
fifty leagues from the mountain, people could onl