The gardens thus represent several periods of development. They were divided into three units: The greenhouse gardens, the cherry walk and pool gardens, and the rose garden. The first of these consisted of three separate parterre gardens within a rectangle framed on the west by the rose and palm houses and on the north by the toolhouse, carnation house, and gardener’s cottage. The cherry walk and pool gardens were located east of this group at a lower level, and progressed from the pergola to the garden house. The rose garden, still further east, had two terraces and contained panel beds. _North Drive and North (Exit) Gate._ The land north of the pavilion was added to the estate in 1905. From the north drive are unsurpassed views of the Hudson, the Shawangunk Range to the west, and the Catskill Mountains to the north. The north gate was erected in 1906. Directly opposite, on the east side of the Albany Post Road, are the Vanderbilt barns, built in 1901. This part of the estate is now in private ownership. _Main (Entrance) Gate and Gatehouse._ These structures date from 1898 and again represent the combination of McKim, Mead, and White-Norcross Brothers. The gatehouse is still used as a residence and is closed to the public. [Illustration: _Main gatehouse._] _White Bridge._ This bridge over Crum Elbow Creek was designed and constructed in 1897 by the New York City engineering firm of W. T. Hiscox and Company. A Melan arch bridge, it was one of the first steel and concrete bridges in the United States. [Illustration: _River gatehouse._] _River Gate and Gatehouse._ The carriage road and Crum Elbow Creek proceed southward, ending near the Hyde Park railroad station at the Hudson River. Near this point is the river gate and gate lodge. These were designed by McKim, Mead, and White, and constructed by Norcross Brothers in 1898. The gatehouse is still used as a residence and is closed to the public. _The Coach Home._ Located on the river hill, a short distance east (or above) the river gate, is the coach house. It was designed by the New York City architect, R. H. Robertson, and erected by Norcross Brothers in 1897. In 1910, R. H. Robertson altered the coach house so it could also be used as a garage. [Illustration: THE VANDERBILT FAMILY TREE (Based on Andrews, _Vanderbilt Legend_, p. 79)]