The argument now employed rests upon the identity of the substance of the gravel with that of the entire flint, which is found in the chalk country; and it goes to prove that the sea had worn away a great deal of that chalk country above the place upon which this body of gravel is now resting; consequently that the sea had formerly flowed over that country covered with gravel, and had dispersed much of that gravel in transporting it to other regions, where that species of flint was not naturally produced. By a parity of reasoning, the gravel produced in the neighbouring regions, and which would be proper to those places, as consisting of their peculiar productions, must have been likewise dispersed and mixed with the surrounding bodies of gravel. But as in the country of which we are now treating, there are considerable regions, the different productions of which are perfectly distinct, we have a proper opportunity of bringing those conclusions of the theory to the test of observation. For this purpose, let us examine the different countries which surround the chalk regions of England, France, and Flanders; if the gravel upon those neighbouring countries contain flint which the country does not naturally produce; and if the mixture of this flint among the gravel, which is proper to the country itself, be with regard to quantity in proportion to the vicinity of the flint country, the Theory will then be confirmed; and there is no doubt that this is so. On the other hand, let us examine the gravel about London, which is far distant from any place that produces quartz; if we shall find a very small proportion of quartz gravel in this flinty soil, we may be assured that the quartz has travelled from a distance, and that the Theory is thus approved. This is actually the case, and I have seen puddingstone containing quartz gravel among the flint. In confirmation of this view of the travelled soil, it may be observed, that in lower Saxony about Hamburgh, and for a great way to the south-west, the gravel is mostly of broken flint, such as is around the chalk countries: Yet it is at a distance from the chalk of Flanders; there is however at Luxemburgh chalk with flint, the same as in England and France. Therefore the flinty soil of that country, in like manner, demonstrates the great destruction of the solid parts, and illustrates the formation of soil by the remainder of the hard parts below, and the alluvion of other parts.