Kasha-Katuwe Tent Rocks National Monument is located about 35 miles southwest of Santa Fe. Precariously perched on many of the tapering hoodoos are boulder caps that protect the softer pumice and tuff below. Some tents have lost their hard, resistant caprocks, and are disintegrating. While fairly uniform in shape, the tent rock formations vary in height from a few feet up to 90 feet (
http://www.blm.gov/pgdata/content/nm/en/prog/NLCS/KKTR_NM.html).