In preparation for the conversion of the land into a city park, Rockefeller hired the Olmsted Brothers firm – and in particular Frederick Law Olmsted Jr., son of the designer of Central Park – to plan the park. Olmsted's design capitalized on the topography to reveal sweeping vistas of the Hudson River and the Palisades. Olmsted Jr. was guided by the four principles of park design that his father had established in creating Central Park: the beautiful, as seen in small open lawns; the picturesque, as shown in wooded slopes; the sublime, represented in the vistas of the Hudson River; and the gardenesque, exemplified by the park's Heather and Alpine Gardens. Olmsted Jr. had a preliminary report in 1927 and conducted a more exhaustive study in 1928-1930. In addition, James W. Dawson was hired to create a park-planting plan.