Porto Cabello is now used to some extent as a point of export; but the only reason why it is not used more extensively is, that between this and the valley there is a hill to be crossed, which could be made respectable as a highway by six sturdy hands in as many days. The country is ripening for immigration. Mr. James Redpath, a talented English-American, and a most acute observer, recently traversed a portion of the Haytien territory, and came to the conclusion that the entire island was capable of sustaining 20,000,000 people. There is not upon it probably one million, and of these the greater portion are in Hayti. The Dominican territory, by far the most extensive and desirable, does not contain much over one-fourth of a million, all told. I say the country is ripening for immigration. The Pike’s Peak fever will ere long be exhausted. Then there is, probably, no more promising field for enterprise than this in the entire new world. Most any point could be made to flourish by the opening of good roads. With Porto Cabello this is peculiarly so. Santiago is the principal interior town. It is the proper place for, and was the former capital. It is situated on the river Yaque, which courses La Vega Real, (the Royal Plains,) and contains about 12,000 inhabitants. The trade of Porto Plata is kept alive mainly from this source; but the mountainous road between them, over which nothing can be transported except by piecemeal on horseback, has been well-nigh the ruin of them both. Porto Cabello is sixteen miles west of Porto Plata. It shuns the St. Mark’s mountain, and it is fair to suppose that, could communication once be established between this and Santiago, and were there the least facilities here for shipping produce, the trade of the interior would inevitably flow in this direction. As to the shipping interest, it was that which first turned our attention hither; for Porto Plata being an unsafe harbor for the winter, vessels had been known to make this port for safety. There are nine feet of water on the shallowest bar, and this once over there are two quiet bays, in either of which a merchantman could ride without an anchor.