This is about just sharing an info on how locality name was derived with reference to certain sthala puranams.
1) Kodambakkam - This locality name is derived by way of Lord Shiva destroying Kar Kodakan snake - Karkodaganpaakam is said to be named as kodambakkam. Reference: Arulmigu Vengeeswarar Koil Sthala puranam.
2) Vadapalani and Mylapore - Nothing to say much on this, as it is self explanatory.
3) Valasaravakkam - There is one temple called Venkatasubramanyar temple - in that sthala puranam - he is a swyambu idol proved by a photo (you can see that if you can visit the temple - this temple is at the backside of Data udipi hotel at Valasaravaakam). The name of this locality is derived as - Valli-sera-vakkam - here the moorthy is single without valli - hence called as Valasaravakkam.

Sad part is that i dont know how saligramam derived its name, although being a resident
If you happen to throw more light on other localities name derivation, it would be really great....