at 110th, 113th, 116th, 118th, and 123rd Streets at the bottom of the cliff, and a restroom at 123rd Street. Morningside Dog Run is an enclosed space for dog owners to bring their dogs to play. Consisting primarily of wood chips over dirt, there are two fenced-in areas. The larger section has multiple levels, separated by a step. The dog run is most easily accessible from the east at 114th Street and from the west at either 114th or 116th Streets. There is also a barbecue area at 121st Street. The Kiel Arboretum is in the northern section of the park from 116th to 121st Streets. The design of the arboretum was based on original plans for Central Park sketched by Olmsted and Vaux in 1858. While later abandoned, these arboretum plans involved paths leading through several hundred species of trees and shrubs. The plans re-emerged when the Kiel Arboretum was built in 1998. Plantings of trees from the Magnoliaceae (magnolia) family and shrubs from the Ranunculaceae (buttercup) and Berberidaceae (barberry) families were used to start the tree collection. Over the years, several playgrounds have been constructed at Morningside Park; there are four playgrounds within the park. The first one, at the bottom of the stairs at 114th Street, was built in 1903–1904 and demolished in 1952. A playground in the northeast corner was constructed in 1935 and renovated in 1941; it was restored several more times, including in 1992 and 2000. Another playground, built in 1955–1956 at Morningside Avenue between 116th and 119th Streets, contains facilities such as shuffleboard and basketball courts, and a playground with a wading pool, swings, slides, and a sandbox. A third play area at 113th Street contains play equipment, while a fourth facility is at 110th Street. In 2008, a new playground opened within the park at 116th Street, replacing part of the playground between 116th and 119th Streets. Geology and topography Morningside Park's distinctive natural geography is a rugged cliff of Manhattan schist rock. The geology is similar to that of Central Park and contains, from top to bottom: Manhattan schist, metamorphosed sedimentary rock; Lowerre quartzite, a metamorphosed rock; Inwood marble, metamorphosed limestone which overlays the gneiss; and Fordham gneiss, an older deeper layer. A large rock formation of Manhattan schist in the park is a visible sign of the bedrock below much of lower and northern Manhattan. Rock outcroppings are prevalent in