Manava Dharmashastra 9.142

9.142

gotrarikthe janayitur na hared dattrimaḥ kva cit
gotrarikthānugaḥ piṇḍo vyapaiti dadataḥ svadhā //

An adopted son shall never take the family (name) and the estate of his natural father; the funeral cake follows the family (name) and the estate, the funeral offerings of him who gives (his son in adoption) cease (as far as that son is concerned).