Gretchen D. Belknap died Nov. 3 at Maristhill Nursing and Rehabilitation Center, Waltham after a period of failing health. She was 87.

She was born Dec. 19, 1930 to the late Roger and Dorothy Dykema, and grew up in Riverside, Conn. She married John (Jack) H. Belknap, also of Riverside, in 1952. They raised their family in Cos Cob, Conn. and summered for many years at Lake Tashmoo.

Gretchen graduated from Greenwich High School and attended both Radcliffe and Bennington colleges focusing on music performance. She was an accomplished cellist. She was a founding member and principal cellist for 25 years with the Greenwich Philharmonia. She was a member of the Greenwich Chamber Players and she taught cello for five decades. After she and Jack relocated to Durham, N.H. in 1989, she lobbied for environmental issues with the League of Conservation Voters.

She leaves behind her children, Peter Belknap, Linda Schier and Sara Gordon, seven grandchildren, four great-grandchildren and several nephews and nieces.

She is predeceased by her parents and her husband, Jack.

Services will be private.

Memorial donations can be made to the Maristhill Nursing and Rehabilitation Center, 66 Newton Street, Waltham, MA 02453.

The family thanks the steadfast and compassionate staff at Maristhill Nursing and Rehabilitation Center for their dedication to Gretchen’s care.