The rocks formed during a period belong to a stratigraphic unit called a system.
The twelve currently recognised periods of the present eon – the Phanerozoic – are defined by the International Commission on Stratigraphy (ICS) by reference to the stratigraphy at particular locations around the world.
You may find it useful for the clear definitions, and for excellent links on a variety of topic.
Santa Fe | (505) 476-5072 May – October: Open Daily 10 a.m. Open most Fridays until 7 p.m.; November – April: Open Tuesday-Sunday 10 a.m.
takes an in depth look into one of the seven wonders of the world, the Great Pyramids of Egypt.
Mystery has surrounded these epic structures for centuries with theories varying from the scientific to the bizarre.
NMArt Santa Fe | (505) 476-5100 May – October: Open Daily 10 a.m. Open most Fridays until 7 p.m.; November – April: Open Tuesday-Sunday 10 a.m. Organized by region, proximity and interest, the Cultural Atlas will help you find where you belong.
From Indian treasures to space exploration, world-class folk art to awesome dinosaurs—our museums and monuments celebrate the essence of New Mexico every day. The Cultural Atlas of New Mexico leads you to historic and cultural places throughout the Land of Enchantment.
NMHistory Your ticket to 15 exceptional Museums and Historic Sites.