Expeditions:   Ravens Ridge -- Rio Santa Barbara -- Pecos Wilderness (Hamilton Mesa) -- Rio Chama -- Cave Creek.

Rio Chama, early October:



Errand list for a drive up the river: finally take a picture of the Great Scenic Moment... visit the dinosaur museum at Ghost Ranch... go on quest for the Perfect Cottonwood.


Just above Abiquiu the highway climbs and you can see back down the valley of the Chama River. Physiographically we are climbing from the Espanola Basin up onto the Colorado Plateau margin, with the sudden appearance of red Chinle rocks to the right of the highway to herald it.

Chinle mudstones of Pictured Cliff formation, with Entrada sandstone above. The Chinle rocks are late Triassic age, something like 215 million years old (see Karen Strom's geological time-chart), and the smooth Entrada sandstones are middle Jurassic, 160 million years old. Or so. In between, 40-million-odd years of other events happened, but the rocks here don't tell us about it.










The very white layer on the background skyline is the Todilto formation, late Jurassic, of limestone and gypsum deposited by evaporation from the warm, shallow, equatorial sea that lay here when "here" was somewhere down near the equator.








Right now, "here" is by milepost 223 on US Highway 84, and the bright red Petrified Forest Formation mudstones make a clear contrast with the buff-colored cliff-forming Entrada sandstones.



The dinosaur quarry at Ghost Ranch is actually in the Rock Springs Formation, a Chinle layer missing from the sandwich in these photos. It would lie just above the Pictured Cliff formation. From this famous quarry, only a few miles from the outcrop above, came a beastie called, well, there's some question about its right name, Coelophysis or Rioarribasaurus; but no question about the beautiful, "fully-articulated"--meaning the bones are all there and in proper relation to each other--six-foot skeletons, which have been excavated there, now carefully picked out from the rocks they had rested in for 200 million years. At the Ruth Hall Museum at Ghost Ranch is a ten-foot skeleton still being worked on. The online Museum of Paleontology at UC Berkeley has a beautiful photo of Ghost Ranch's carefully exposed specimen, at Coelophysis. Here's a young Rioarribasaurus. Here's a drawing of Coelophysis/Rioarribasaurus, on the New Mexico Museum of Natural History's Dinosaurs in New Mexico page.

Past Ghost Ranch, the highway swings away from the river and climbs up again, northwards to Tierra Amarilla and Chama. A long dirt road, a car-eater in many seasons but firm and dry today, follows the Chama River west between the cliffs of the Rio Chama Wilderness, to dead end (for all but river rafters) at the monastery at Christ in the Desert. I wanted to find a perfectly shaped, perfectly yellow cottonwood with the river in the foreground and cliffs behind ... and then sit right there by the river, to listen to the water flowing by.







....... . . . . sit right here by the river and listen to the water flowing by.
Expedition October, 1995.
Page updated, January 12, 2000.
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