Trap rock, form of igneous rock exhibiting polygonal vertical fractures
rock | Rock music | rock music | punk rock | alternative rock | indie rock | rock and roll | Punk rock | rock band | Rock Band | 3rd Rock from the Sun | Kid Rock | 30 Rock | Rock | pop rock | folk rock | Little Rock, Arkansas | Indie rock | Alternative rock | Rock Band 3 | classic rock | Kill Rock Stars | Rock and Roll Hall of Fame | Rock and roll | Christian rock | Chris Rock | We Will Rock You | Little Rock | Classic rock | Rock Hudson |
The trap rock which underlays most of the park contains granite intrusions which has caused some fracturing.