There is perhaps no geological problem of greater interest than that by which the conditions of the globe, in respect to the distribution of land and water, at the epoch of the coal formation, might be determined, if the necessary data for its solution could be obtained. We possess sufficient evidence to shew that, since that period, most of the continents and islands of the present day have been elevated above the waters, under which they were originally formed; but such proofs are altogether wanting when we endeavour to restore, in imagination, the probable extent of the older formations that might then have existed as dry land, but which now lie buried in the depths of the ocean, or have since been covered by an accumulation of more recent deposits.