There is a Prigmore Family Tree, http://trees.ancestry.com/tree/12356415/person/62604076http://trees.ancestry.com/tree/12356415/person/62604076 which contains your Mullins family. I thought you might want to make contact with the owner.
Amasa's father was Burel Mullins b. 1794. His mother was Elizabeth Strong b. 1798.
His sister was b. 1822 in Jefferson City, Jefferson Co. TN. On 17 Jan 1841 she married Lewis Reneu who was born 1817. They had many children who are listed on the Prigmore Family Tree.
Ellen died 26 Nov 1892 in Dandridge, Jefferson Co., TN.
Of course you need to verify all information provided in someone else's family tree before you enter it into your own.
In 1870 Amasa and family were living with the Pratt family in California.
Amasa Mullen, b. 1829, TN.
Angeline, wife, 35.
Phebe J., 5.
In 1872 Ammasa Lauisdell Felorions Baldwin Mullins was living in Mariposa Co., CA.
Source: Calif. Voter Registrations 1866-98.
In 1880 the Mullins family was living in Township 9, Range 13, Merced Co., CA.
Amasa Mullins, b. TN, 53, farm laborer.
Angeline, wife, b. Mou [MO?}, 47.
Angus, b. CA, 17, farm laborer.
Martha, b. CA, 15.
David, b. CA, 13.
Emily, b. CA, 11
Jame, dau, b. CA, 9.
Lucy, b. CA, 8.
Lillie, b. CA, 5.
James, b. CA, 3.
In 1884 Amasa Mullins, 56, was living in Fresno Co., CA
Born: abt. 1828, TN
Occupation: Farmer, Buchanan.
Source: Voter Registrations
In 1892 Amasas Lansdel "P" "B" Mullins
Residence: Selma Precinct, Fresno, CA
Source: same as above.
In 1910 Amasa is living with his son Ameda and family in Corcoran, Kings Co., CA.
Ameda L. Mullins, b. CA, 48, marr 22 yrs, manager general farm.
Molly L., wife, b. CA, 39, had given birth to four children who were all alive in 1910.
Adeline, b. CA, 18, single.
Cicero, son, b. CA, 16, teamster farm.
Amasa, father, widow, b. TN, 88.
Chester A., head his household, b. CA, 21, farm laborer working out.
Ella B., wife, b. AR, 18.
Nelson Ray, brotherlaw, b. AR, 6.
I didn't find death info for Amasa in Ancestry or FamilySearch.
Selma is located in Fresno Co. There is a Fresno county obituary volunteer at http://freepages.genealogy.rootsweb.ancestry.com/~obitl/volca.htmlhttp://freepages.genealogy.rootsweb.ancestry.com/~obitl/volca.html
Scroll down to Fresno Co.
His obituary might have been published in Kings Co., CA. The Kings County Library, http://www.kingscountylibrary.org/res/hstk.htmhttp://www.kingscountylibrary.org/res/hstk.htm has newspapers on microfilm.