“Let us understand this. There is a system of growth, a law, if I may so term it, of geomorphic sameness in the development of large, or for that matter, small geological territories. The familiar story of the growth of our North American continent has been often told. It is a commonplace of text books. The wide, triangular Archæan nucleus to the north, the oldest rocks--outlines and outliers down the east, and the same in the west--drew the framing limits of the continent at the first, to be filled in, up and out, by the momentous additions through the ages of advancing time. In Europe less well or simply defined boundaries, the growth together rather of divided islands, prevailed, and the picture of development was quite varied, from the picture in this western world. Again in Africa, with edges of uplift and centres of depression another geological tale with its incidents and accessories infinitely modified, comes into view. And in this prevalence of structural style, we, geologically speaking, find a prevalence of certain geological phases or conditions. “What were these in the growth and disappearance of this Columbian continent? What they have been, we can, with rational probability, assume they will be. “The Columbian continent, I have called a dismembered, a fractionized continent. If from Cuba through Haiti, Porto Rico, and the lesser Antilles one land surface obtained, and the now submerged and radiating gorges, found only as submarine canyons, were above the ocean, becoming, as Prof. Spencer has laboriously proven, sub-aerial river valleys, we should have one presumable phase of this continent, the phase of its maximum cohesion and extension. And such a phase is measurably or, for purposes of argumentative inference, sensibly established. It is said with careful premeditation by Hill that ‘the numerous islets of its eastern border, the Bahamas and Windward chain, which extend from Florida to the mouth of the Orinoco, are merely the summits of steep submarine ridges, which divide the depths of the Atlantic from those of the Gulf of Mexico, and Caribbean sea; were their waters a few feet lower, these ridges would completely landlock the seas from the ocean.’