31. Shipworm-bored petrified wood is the North Dakota state fossil. 32. The lithic technology suggests extensive reliance on the locally available petrified wood , rhyolite, and quartzite. 33. Petrified wood rings the top and punches into the edges like ragged soldiers on guard.34. Similarly, coral, petrified wood and other organic remains or porous rocks can also become agatized. 35. Due to the Sonoma Mountain's ancient volcanism, Penngrove is rich with obsidian and petrified wood . 36. Examples include petrified wood and pyritized gastropod shells. 37. Petrified wood is extremely common in the creek.38. Contemporary plant fossils from Nevada include " twigs " of petrified wood preserved in Eureka County. 39. Those lignite mounds coincide with most of the petrified wood and fossils found in the Wilderness. 40. The Sentinel Butte contains an extensive stump-bearing petrified wood bed above the contact at the site.
