So what is Pahoehoe lava doing in the Rio Grande del Norte National Monument?
Pahoehoe is the second most abundant type of lava flow. Pahoehoe lava is characterized by a smooth, billowy, or ropy surface. Pahoehoe flows tend to be relatively thin, from a few inches to a few feet thick.
The geologic landscape along the Rio Grande from Colorado border to Sante Fe is predominantly volcanic. At least 35 volcanic vents have been identified on the Taos Plateau, in the Rio Grande del Norte National Monument.
Pahoehoe lava is a type of basaltic lava which forms by many small breakouts of lava from an over-crusted inflating flat, irregular flow. It is typical for shield volcanoes like the ones found on the West side of the Rio Grande river.
(click on images to enlarge)