elius_, and called _Mons
Olympus_ (though I think somewhat improperly, being rather a vale) and
represented by the Figure X. of the 38. _Scheme_, and also by the Learn'd
_Ricciolus_, who calls it _Hipparchus_, and describes it by the Figure Y,
yet how far short both of them come of the truth, may be somewhat perceiv'd
by the draught, which I have here added of it, in the Figure Z, (which I
drew by a thirty foot Glass, in _October_ 1664. just before the Moon was
half inlightned) but much better by the Reader's diligently observing it
himself, at a convenient time, with a Glass of that length, and much better
yet with one of threescore foot long, for through these it appears a very
spacious Vale, incompassed with a ridge of Hills, not very high in
comparison of many other in the Moon, nor yet very steep. The Vale it self
ABCD, is much of the figure of a Pear, and from several appearances of it,
seems to be some very fruitful place, that is, to have its surface all
covered over with some kinds of vegetable substances; for in all positions
of the light on it, it seems to give a much fainter reflection then the
more barren tops of the incompassing Hills, and those a much fainter then
divers other cragged, chalky, or rocky Mountains of the Moon. So that I am
not unapt to think, that the Vale may have Vegetables _analogus_ to our
Grass, Shrubs, and Trees; and most of these incompassing Hills may be
covered with so thin a vegetable Coat, as we may observe the Hills with us
to be, such as the short Sheep pasture which covers the Hills of
_Salisbury_ Plains.

Up and down in several parts of this place here describ'd (as there are
multitudes in other places all over the surface of the Moon) may be
perceived several kinds of pits, which are shap'd almost like a dish, some
bigger, some less, some shallower, some deeper, that is, they seem to be a
hollow _Hemisphere_, incompassed with a round rising bank, as if the
substance in the middle had been digg'd up, and thrown on either side.
These seem to me to have been the effects of some motions within the body
of the Moon, _analogus_ to our Earthquakes, by the eruption of which, as it
has thrown up a brim, or ridge, round about, higher then the Ambient
surface of the Moon, so has it left a hole, or depression, in the middle,
proportionably lower; divers places resembling some of these, I have
observ'd here in _England_, on the tops of some Hills, which might have
been caus'd by some Eart