The amount of SALT in the ocean is a circumstance which geologists have not, I think, sufficiently considered. This salt, if precipitated, would, it is believed, yield a solid range of mountains equal to that of the entire Himalaya. Now, mighty rivers run into the sea, as those of La Plata, Amazons, Mississippi, St. Lawrence, Orinoko, and many others; but _none of these rivers are salt_; they are enormous bodies of fresh water. How, then, does the ocean maintain everywhere its saline character unimpaired? not to ask, whence did so much salt come? There is, indeed, a hill of salt in Spain, and there are mines of rock-salt in Poland and Hungary; but the _effort_ which was made, so to speak, when the proportion now existing in the ocean was squeezed out of the huge terrestrial sponge, must far have exceeded that of any subsequent addition or contribution. The ocean itself, as _girding_ this globe, is a prodigious mass of water, indeed. But, if we remember the size of the globe itself, as given by its diameter, Ocean appears like a rain-pond. For, if we call its average depth five miles—and it cannot be more than this, may be much less—such a watery envelope would be represented in its proportion to the solid sphere which it surrounds, by a coating of varnish of the thickness of this paper lying on a globe which is twenty feet in diameter. The COAL-MEASURES are also a remarkable item in the list of substances met with in beds and ranges, and claiming to be considered as rocks—for the coal is a _petrifaction_, perhaps a partial _crystallization_—but due to the deposition of vegetable matter, subjected afterwards to enormous hydrostatic pressure. We have no true estimate of their amount as yet, for fresh mines are being continually discovered; but here seems to consist the chief proportion of CARBON, as developed in this part of the visible creation. CHALK constitutes one-eighth part of the crust of this globe. The mass of this must have been thrown up _at once_, when the atmosphere was eliminated, and the waters separated, and the sphere became condensed and solid. It is a “carbonate of lime” in its chemical description, and there is abundance of the limestone-rock all over the world; but it is very difficult to extract from this, in any quantity, the soft, friable, slightly unctuous mineral which goes by the name of chalk (Latin, “calx”).