Bhagwat Purana says that the Manu lived near the Banks of Tamiraparani. Thus the Solar Dynasty has its origins in South India and later went to North. At least that is what the Bhagwta Purana says.
Also remember reading the Matsya avatar happened in Madurai at the "Kruthamala" river. How many of us know that like Vaigai, Kruthamala river was also flowing - even about 30 years back as a small cannal. Dont know about the current status