गगनात् from sky, शङ्करशिर: on the head of Shankara, तत: from there, धरणिम् earth, आश्रिता resorted, तत्र there, जलम् waters, तीव्रशब्दपुरस्कृतम् culminating in intense sounds, व्यसर्पत had flown.

From the sky on to the head of Shankara and thence Ganga resorted to the earth. There it flowed forward with a roaring sound.