The curiosities included in the various State and Territorial displays, were too numerous to give an account of them all. Special features were--a miniature coal-mine shown by Iowa; a section of the world-renowned Mammoth Cave in Kentucky; a statue of rock salt representing Lot's wife, a contribution from Louisiana; a tunnel containing a double tramway for the carrying of ore displayed by Pennsylvania; a model of the largest lead-reducing works in the world from Missouri; and a miner's cabin built of mineral specimens from the different counties in the territory of New Mexico. All the mining exhibits--in their selectness and profusion--gave evidence of the inexhaustible wealth yet stored up for man's future uses notwithstanding the geological fact, that the earth's crust has no great profundity compared with its diameter. The "_Golden Door_" an immense archway enriched to an extraordinary degree with carvings, paintings, and overlaid with gold leaf, ushered us into the TRANSPORTATION BUILDING. It was dedicated to present the origin, growth, and development of the various methods of abridging distance used in all parts of the inhabited globe--from remote antiquity up to the present day. We were charmed with a striking vista of richly ornamented colonnades which added considerably to the impressive effect of the exhibits. The latter comprised three general divisions: the railway--marine--and ordinary road vehicle transportation. To the first mentioned--as most important--a space of over eight acres had been devoted. About one-eighth of this area was covered with the "Railways of the World," an exhibit of the Baltimore and Ohio Railway Co., showing the development of locomotives and cars from the earliest days to the modern time. One of the unique features in the American Railroad Section was the operation of air brakes on a train of a hundred cars, the longest ever witnessed in a single series. In the center aisle of the annex, we inspected the chief display of the Pullman Company, a complete train sumptuously equipped. It embraced specially built Pullman Cars of the most luxurious character. The representation of the New York & Chicago Limited Express was, without doubt, the finest railway train ever constructed. We received a very adequate idea of the wonderful achievements--evincing the genius of the age in which we live--in railway conveyance, by the out-of-door exhibit of the N.Y. Central & Hudson R.R. Co., at the southern extremity of the annex. Here, the contrast between past and present was most sharply drawn: The first train, ever used for traffic in this country, and running between Schenectady and Albany, N.Y.--the opening of this road was celebrated on the 24th of September, 1831--with its simple De Witt Clinton engine, was beside a locomotive of gigantic proportions, the fastest in the world. This stupendous piece of machinery constituted a portion of the Vanderbilt enterprise.