Now, to see how little the situation of the strata influences the shape of the valleys, I shall transcribe the two paragraphs immediately following that which has given occasion to the present discussion.

“Un peu au-dela de Nux, la vallee cesse d’etre large et plane, comme elle etoit dans le environs de la cite; elle devient etroite et tres variee; la sterile et sauvage, ici couverte de vergers et de prairies arrosees par la Doire.

“Sec. 961.  Les couches des montagnes a notre gauche, qui depuis la cite avoient constamment couru a l’est et monte au nord, paroissent changer a un quart de lieue du village de Chambaise, qui est a une lieue et un quart de Nux.  Elles montent d’abord au sud-est, et peu plus loin droit au sud, tandis que l’autre cote de la vallee elles paroissent monter a l’est.”

In every mountain, and in every valley, the solid parts below have contributed in some manner to determine the shape of the surface of the earth; but in no place is the original shape of the earth, such as it had first appeared above the sea, to be found.  Every part of the land is wasted; even the tops of the mountains, over which no floods of water run, are degraded.  But this wasting operation, which affects the solid rock upon the summit of the mountain, operates slowly in some places, compared with that which may be observed in others.  Now, it is in the valleys that this operation is so perceptible; and it is in the valley that there is such a quick succession of things as must strike the mind of any diligent observer; but this is the reason why we must conclude, that at least all the valleys are the operation of running water in the course of time.  If this is granted, we have but to consider the mountains as formed by the hollowing out of the valleys, and the valleys as hollowed out by the attrition of hard materials coming from the mountains.  Here is the explanation of the general appearance of mountain and valley, of hill and dale, of height and hollow; while each particular shape must have its dependence, consequently its explanation, upon some local circumstance.

But, besides the general conformation of mountains and valleys, there may be also, in the forms of mountains, certain characters depending upon the species of substances or rocks of which they are composed, and the general manner in which those masses are wasted by the operations of the surface.  Thus there is some character in the external appearance of a hill, a mountain, or a ridge of hills and mountains; but this appearance is generally attended with various circumstances, or is so complicated in its nature, as to be always difficult to read; and it is but seldom that it affords any very particular information; although, after knowing all the state and circumstances of the case, I have always found the appearances most intelligible, and strictly corresponding with the general principle of atmospheric influence acting upon the particular structure of the earth below.