The Barnum Family, 1517-1904 calls her Clarisa Barnum, with one "s".
In the 1870 US Census for Hastings, Barry County, Michigan Clarissa McMurray and family were enumerated as follows:
Dwelling #121; Family #106
McMurray, Clarrisa [sic]; 45; F; W; Keeping house; Real property $1,000; Personal property $200; b. New York
McMurray, Lafayette; 21; M; W; Farm laborer; b. Michigan; Male citizen of US of 21 years of age and upwards
McMurray, Madison; 19; M; W; Farm laborer; b. Michigan
McMurray, Lucetta; 17; F; W; Domestic help; b. Michigan
McMurray, Eugene; 9; F [sic]; W; b. Michigan; Attended school within the census year
McMurray, Eva; 6; F; W; b. Michigan; Attended school within the census year
Her death record states that she was a housewife and gives the cause of death as Consumption of the Lungs (what we now call Tuberculosis).
She was buried in Riverside Cemetery, near her son Lafayette and daughters-in-law Nora (wife of Samuel Eugene) and Mary J. (wife of Madison).