Servilleta Basalt: The Black Rock That Built the Rio Grande Gorge
West of Questa, the land opens into the broad Taos Plateau, and then, almost without warning, it drops away. At the Wild Rivers Recreation Area, where the Red River meets the Rio Grande, you can stand at the rim and look into a gorge the Bureau of Land Management describes as up to 800 feet deep, carved through layers of volcanic basalt flows and ash interbedded with sand and gravel. The dark rock in those walls has a name every local rockhound should know: Servilleta Basalt.