Frederick Roths's Mother Goose Statue at the entrance to Rumsey Playground in Central Park, July 2015. The 1938 Parks Department press release[1] says:

The Department of Parks announces that an interesting statue depicting famed characters of the Mother Goose series of fairy tales, has been erected in the circle at the entrance to the Mary Harriman Rumsey children's playground in Central Park, Manhattan, formerly the site of the old Casino.

The statue consists of a large figure of the witch who is astride the goose's back; then on the east and west sides in bas-relief there are figures of Humpty Dumpty, Old King Cole, Little Jack Homer, Mother Hubbard, and Mary and Her Little Lamb.

This amusing piece of statuary was carved out of a thirteen ton piece of Westerly Granite by W. P. A. craftsmen, working under the jurisdiction of the Park Department. It was conceived and designed by Frederick G. Roth, who also designed and executed the carved group of "Alice in Wonderland" characters in the Sophie Irene Loeb Memorial erected in the Heckscher Playground in 1936.

References:

1. New York City Parks Department press release of June 17, 1938.
2. Dimmick, Lauretta, and Donna J. Hassler, American Sculpture in the Metropolitan Museum of Art: A catalogue of works by artists born between 1865 and 1885, Volume 2, Metropolitan Museum of Art, Jan 1, 1999, 788 pages: “As chief sculptor for the New York Parks Department under the Works Progress Administration between 1934 and 1936, Roth produced outdoor sculptures for Central Park including ... Mother Goose (1938, Mary Marriman Rumsey Playground) with low-relief scenes from nursery rhymes on the base.”[2]
3. The Landscapes of Robert Moses, Sitelines, A publication of the Foundation for Landscape Studies, v.III, No.1, Fall 2007, pp.3-4: “[Robert] Moses's taste in public art soon became apparent. Instead of statues commemorating important figures in literary, cultural, and political history, he commissioned works of a whimsical nature most of which were based on children's stories. In 1938 he used Works Progress Administration (W.P.A.) funds to erect a granite statue of Mother Goose by Frederick George Richard Roth (1872-1944). With soaring cloak, she sits astride a flying goose at the entrance to the Rumsey Playground. The statue's bas-relief base depicts Little Jack Horner, Humpty Dumpty, and Little Bo Peep.”[3]
4. Mother Goose: History, New York City Department of Parks website: “Location: Rumsey Playground, E. Drive at 72nd St.; Sculptor: Fred. G.R. Roth, Walt. Beretta; Description: Group on pedestal; Materials: Stony Creek and Deer Isle granites; Dedicated: 1938.”
5. Frederick Roth, Wikipedia.