We cannot avoid suggesting here, to the owners and workers of coal property in Virginia, the propriety of investigating the strata through which they necessarily pass in their mining operations, with reference to the discovery of argillaceous iron-stone, with more minuteness than hitherto they have done--if indeed, (which we are inclined to doubt,) their attention has been in any degree directed to such examination. It is from this species of iron-stone, accompanying coal-strata, that Great Britain derives at least nineteen twentieths of the metals which she possesses in such abundance, and to which, in connection with its convenient location in the immediate vicinity of the fuel necessary in its reduction, she owes her towering eminence as a manufacturing country. The coal formation of Virginia contains the same clays, shales, sandstones and slates, and these are characterized by the same vegetable impressions that mark the series in other countries. And may we not reasonably ask, why should we hastily conclude this usual concomitant of the coal strata in England, Scotland, France and Germany, to be wanting here; or rather, why may not we hope to find it equally abundant in our own coal district. We are induced to urge this suggestion the more, from the circumstance, that this species of ore presents in its external characters, so little indicative of its metallic nature or chemical composition, that but for its greater weight, it might well escape the notice of an inexperienced or unobservant eye, unless arrested by some such hope as we have been induced to hold out. Even in England, where from its great abundance it might have been expected to be generally better known, instances have occurred in some districts, of its being wastefully misapplied, through ignorance, to the common purpose of mending the roads. The immense benefits that would result from success attending a research directed to this object, as well to the city of Richmond, as to a few fortunate individuals, are too obvious to require comment. It is sufficient to remark, that it would prove an abundant source of individual wealth, and would, in connection with her other great advantages and increasing facilities of transportation, be the means of elevating the metropolis of Virginia to an exalted rank in the class of large cities, and enable her to vie in importance with the proudest seat of manufactures, or the most extensive emporium of commerce.