In Prospect Park, the geological structure of the parcel - a transitional landscape which straddles the terminal moraine and outwash plain at the southern extent of the Wisconsin glacier - established three distinct types of landform which Vaux and Olmsted exploited. The flat expanse of the outwash plain to the south was developed into the vast lake; the rolling terrain of the terminal moraine was developed into the picturesque ravine; and the glaciated till landform to the north was transformed into the Pastoral or Beautiful undulating long meadow, which is defined by real and constructed eskers.