250. An argument founded on facts very similar to some of the preceding, and leading to the same conclusion, is employed by the mineralogist to whom the Neptunian system owes its chief support. Werner, in his observations on volcanic rocks and on basaltes, has rested his proof of the aqueous formation of the latter, on their interposition between beds of stone in mountains regularly stratified, and obviously formed by water. He describes an instance of this in the basaltic hill of _Scheibenberg_; and the facts, though most of them are not uncommon, are highly deserving of attention. Near the top of this hill, and above the basaltic rock which composes the body of it, he tells us, that there was a sand-pit; a circumstance which he appears to consider as not a little singular. It was, however, at the bottom of the hill, that he met with the appearances which chiefly attracted his notice: "First," says he; "or lowest, was a thick bank of quartzy sand, above that a bed of clay, then a bed of the argillaceous stone called wacke; and upon this last rested the basaltes." "When I saw," adds he, "the three first beds running almost horizontally under the basaltes, and forming its base; the sand becoming finer above, then argillaceous, and at last changing into real clay, as the argil was converted into wacke in the superior part; and, lastly, the wacke into basaltes; in a word, when I found a perfect transition from pure sand to argillaceous sand, from the latter to a sandy clay, and from this sandy clay, through many gradations, to a fat clay, to wacke, and at last basaltes, I was irresistibly led to conclude, that the basaltes, the wacke, the clay, and the sand, are all of one and the same formation; and that they are all the effect of a chemical precipitation during one and the same submersion of this country."[134] [Footnote 134: "Combien je fus surpris de voir en arrivant au fond, un epais _banc de sable quartzeux_, puis au-dessus une _couche d'argile_, enfin une couche de la pierre argileuse nommée _Wacke_, et sur celle-ci reposer le _basalte_. Quand je vis les trois premiéres couches s'enfoncer _presqu' horizontalement sous le basalte_, et former ainsi sa _base_; le sable devenir plus fin au-dessus, puis argileux, et se changer enfin en vraie argile, comme l'argile se convertissoit en wacke dans sa partie supérieure; et finalement la wacke en basalte; en un mot, de trouver ici une _transition parfaite_ du _sable pur_ au _sable argileux_, de celui-ci à _l'argile sablonneuse_, et de _l'argile sablonneuse_, par plusieurs gradations, à l'argile _grasse_, à la _wacke_ et enfin au _basalte_.