- The Tonian (from Ancient Greek: τόνος, romanized: tónos, meaning “stretch”) is the first geologic period of the Neoproterozoic Era. It lasted from 1000 to 720 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based on radiometric chronometry. The Tonian is preceded by the Stenian Period of the Mesoproterozoic Era and followed by the Cryogenian.
- Columbia Hills (wa100.dnr.wa.gov)
Columbia Hills State Park is a 3,338 acre park on the banks of the Columbia River in southern Washington. The park is bordered on the north by DNR’s equally large Columbia Hills Natural Area Preserve, where hikers can climb to the top of the ridge to enjoy scenic views from Stacker Butte. The area gives a sense of the rich geologic and cultural history of the Columbia River Basin and provides gorgeous views of yellow arrowleaf balsamroot-carpeted hillsides during the spring wildflower bloom. Rock climbers and geologists alike can appreciate Horsethief Butte, whereas those looking to fish, swim, and enjoy a day in the sun will find an ideal day use area at Horsethief Lake. A trip to this area gives visitors the opportunity to learn about geology while enjoying a relaxing weekend excursion.