When you get to the park you’ll walk upon a 10 million years old volcano, today Round Top is one of the tallest peaks in the area made up of lava.
Take a self guided geology tour and a hike. I was on a mission for something a bit mysterious, a volcanic labyrinth.
Hike to Quarry Pit 2 and look down, you’ll find your way. 
The soft velvety hills are mellowing, the views in the park are stunning,
and you’ll find plenty of interesting flora and fauna.
There are numerous trails to take including a section of the 31-mile East Bay Skyline National Recreation Trail, Bay Area Ridge Trail, and of course to the summit of Round Top.