t, and the Channel, on the south, the chalk
is largely hidden by other deposits; but, except in the Weald of Kent and
Sussex, it enters into the very foundation of all the south-eastern
counties.

Attaining, as it does in some places, a thickness of more than a thousand
feet, the English chalk must be admitted to be a mass of considerable
magnitude. Nevertheless, it covers but an insignificant portion of the
whole area occupied by the chalk formation of the globe, much of which
has the same general characters as ours, and is found in detached
patches, some less, and others more extensive, than the English. Chalk
occurs in north-west Ireland; it stretches over a large part of France,--
the chalk which underlies Paris being, in fact, a continuation of that of
the London basin; it runs through Denmark and Central Europe, and extends
southward to North Africa; while eastward, it appears in the Crimea and
in Syria, and may be traced as far as the shores of the Sea of Aral, in
Central Asia. If all the points at which true chalk occurs were
circumscribed, they would lie within an irregular oval about 3,000 miles
in long diameter--the area of which would be as great as that of Europe,
and would many times exceed that of the largest existing inland sea--the
Mediterranean.

Thus the chalk is no unimportant element in the masonry of the earth's
crust, and it impresses a peculiar stamp, varying with the conditions to
which it is exposed, on the scenery of the districts in which it occurs.
The undulating downs and rounded coombs, covered with sweet-grassed turf,
of our inland chalk country, have a peacefully domestic and mutton-
suggesting prettiness, but can hardly be called either grand or
beautiful. But on our southern coasts, the wall-sided cliffs, many
hundred feet high, with vast needles and pinnacles standing out in the
sea, sharp and solitary enough to serve as perches for the wary
cormorant, confer a wonderful beauty and grandeur upon the chalk
headlands. And, in the East, chalk has its share in the formation of some
of the most venerable of mountain ranges, such as the Lebanon.

What is this wide-spread component of the surface of the earth? and
whence did it come?

You may think this no very hopeful inquiry. You may not unnaturally
suppose that the attempt to solve such problems as these can lead to no
result, save that of entangling the inquirer in vague speculations,
incapable of refutation and of verification. If