Follow the river south and a bit west. I haven't been down there, but you can see the cloud on the map that marks the area to go to. 
I have no idea if Temple is the second or third dungeon, I just felt it was third, but I'm starting to think it's second now. After you've done both dungeons, I'd appreciate it if let me know, which you felt was harder. Same for everyone else.
Lore tidbit: There is a jungle kingdom to the south of Silverpine, called, Vraxis full of raptorfolk. I have no idea where it is southwards, but I suspect it's like Thalassar and not accessible.