OJITO WILDERNESS

Formation Name: MORRISON

Rock Type(s): Sandstone, Siltstone, Shale

Geologic Time Period: LATE JURASSIC

Time of Deposition (millions of years ago): 150 to 144

Depositional Environment: rivers, flood plains, lakes, wetlands

Common Fossils Found: Petrified wood, Sauropod dinosaurs (herbivores): Allosaur dinosaurs (carnivores)

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Formation Name: DAKOTA SANDSTONE

Rock Type(s): Sandstone

Geologic Time Period: MIDDLE CRETACEOUS

Time of Deposition (in millions of years ago): 108 to 94

Depositional Environment: marine shoreline, beaches

Common Fossils Found: marine invertebrates (e.g., bi-valves), fishes

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Formation Name: MANCOS SHALE

Rock Type(s): Shale

Geologic Time Period: LATE CRETACEOUS

Time of Deposition (in millions of years ago): 85 to 80

Depositional Environment: marine -- terrestrial sediments washed into shallow sea

Common Fossils Found: marine invertebrates (e.g., spiraled ammonites), sharks

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At the basin’s southeastern edge, The Ojito’s Wilderness’ countless natural sculptures and sweeping vistas are only part of the reason why it is New Mexico’s newest official wilderness area. Bonsai ponderosa pines and venerable, character laden juniper trees clinging to bare rock add to the beauty. Petrified wood litters the hoodoo galleries.

Ojito’s lowest, and the San Juan Basin’s second oldest layer, the widespread, 160 million year old Morrison formation , in other southwestern states had produced the most exceptional Jurassic dinosaur fossils in the world. New Mexico seemed left out of the picture until 1985, when Ojito divulged 8 vertebrae and several leg bone fragments from the 120 feet long, 100 ton Seismosaurous which at the time was the largest dinosaur species yet discovered. Ojito’s upper two layers, the Dakota Sandstone and later Mancos Shale, chronicle an ancient ocean as it slowly expanded and flooded the basin. Deep water marine fossils characterize the Mancos layer.

OJITO DIRECTIONS—Turn west off 550 about 2 miles south of San Ysidro village onto well marked Cabezon Road. Immediately take the left fork and at all the following forks take the one that appears most traveled. A sign about 4 miles in marks the wilderness area boundary. The best badlands lie in the northwest corner, but you’ll find entertaining rock forms throughout the area.

FOR MORE INFO—Donna Dudley, Recreation specialist at the Albuquerque BLM office, 505-761-8700