In plain words
The poet, of Kaṇṭam: He blew the right-whorled conch whose mouth roars, hurled the discus that spits fire, and there [when he measured the worlds] sent rolling the heads of the asuras who faced him in battle: the dwelling of our Puruṣōttama is the eminent city called Kaṇṭam, on the Gaṅgā, whose waters, after resting in the hand of the four-faced [Brahmā], on the feet of the four-armed one [Trivikrama] and in the matted locks of Śaṅkara, flow down carrying bright-faced gems.