The processes that created Capulin Volcano also created extraordinary forms around its base. The lava flows formed a resistant cap on the easily weathered sedimentary rocks, which protected this underlying rock from erosion while all the surrounding rock washed away. The result is the high, flat-topped mesas, such as Raton Mesa, Mesa de Maya, and Johnson Mesa.

At Capulin Volcano moving lava developed a crust on the surface as it cooled and in places this surface was “wrinkled” by the flowing lava beneath producing pressure ridges.

Partially cooled lava, pushing through cracks like toothpaste from a tube, solidified into semi-rounded squeeze-ups called tumuli.

Various volcanic bombs were also formed as blobs of partly molten lava were thrown high up into the air and cooled as they fell back to the earth: breadcrust, “cow dung,” spindle, and ribbon bombs are the most common volcanic bombs at the monument.