Garudapurana 3.15.4

3.15.4

sa evaṃ saṃkarṣaṇanāmadheyaḥ pradyumnanāmā ca sa eva viśrutaḥ /
sarasvatībhāratīsarjanārthaṃ sa eva devyā mūlarūpo babhūva //

He whose name was Saṃkarṣaṇa was also famed under the name Pradyumna; / for the sake of creating Sarasvatī and Bhāratī, he became the root form of the goddess.