You say he settled in Trinity, what happened to wife Phebe?Is this him with another "slightly" younger wife?
1880 census Trinity Co, TX:
Category: Name;Relationship to head of household; Marital Status; Gender; Race; Age; Birthplace; Occupation; Father's Birthplace; Mother's Birthplace.
Paul MC GARSelfMMaleW28ALFarmsGAGA Maud R. MC GARWifeMFemaleW17TXKeep HouseSCAL Wm. G. MARTINFatherLWMaleW88SCFarms------ Mary G. MARTINDauSFemaleW19MSSCAL Wm. E. SHEFFIELDOtherSMaleW40OHNurserymanCTPA