Shiva Purana
सा गंगा गौतमी नाम्ना लिंगं त्र्यंबकमीरितम् ॥ ख्याता ख्यातं बभूवाथ महापातकनाशनम् ॥ ५०॥
Gaṅgā there became famous as Gautamī. The phallic image became famous by the name Tryambaka. Both are destructive of great sins.
english translation
sA gaMgA gautamI nAmnA liMgaM tryaMbakamIritam ॥ khyAtA khyAtaM babhUvAtha mahApAtakanAzanam ॥ 50॥
hk transliteration by Sanscript