In unstratified crystalline rocks, wholly destitute of animal or vegetable remains, we search in vain for those most obvious evidences of contrivance, which commence with the first traces of organic life, in strata of the transition period; the chief agencies which these rocks indicate, are those of fire and water; and yet even here we find proof of system and intention, in the purpose which they have accomplished, of supplying and accumulating at the bottom of the water the materials of stratified formations, which, in after times, were to be elevated into dry lands, in an ameliorated condition of fertility. Still more decisive are the evidences of design and method, which arise from the consideration of the structure and composition of their crystalline mineral ingredients. In every particle of matter to which crystallization has been applied, we recognize the action of those undeviating laws of polar forces, and chemical affinity, which have given to all crystallized bodies a series of fixt definite forms and definite compositions. Such universal prevalence of law, method, and order assuredly attests the agency of some presiding and controlling mind. A further argument, which will be more insisted on in speaking on the subject of metallic veins, may be founded on the dispensation whereby the primary and transition rocks are made the principal repositories of many valuable metals, which are of such peculiar and indispensable importance to mankind.
CHAPTER V.
Volcanic Rocks, Basalt, and Trap.
In the state of tranquil equilibrium which our planet has attained in the region we inhabit, we are apt to regard the foundation of the solid earth, as an emblem of duration and
