The Dink Network

I cant find the entrance to the Dragons Cave. The walkthrough says its at a rock with scratches where the game first began. I've gone to the area where the game began, and to the rock with a face etched into it, but nothings happening.
I've also walked around the whole game looking at, blowwing up, burning down, and kicking every rock, cactus, or critter I've come across. Still, I cant figgure out how to get into the Dragons Cave.
please help.