Enigmatic quartzite piles of La Tierra-Las Dos subdivisions area, Santa Fe County, New Mexico
— Robert L. Borton

Six miles (10 km) northwest of Santa Fe are located eight scattered and isolated piles of quartzite boulders that, by their very presence, create a puzzling geologic problem. Recent subdivision road building has made six of the piles easily accessible and one can drive directly to two of them (piles 4 and 7). Only Baldwin (Spiegel and Baldwin, 1963), in a comprehensive study of the geology of the Santa Fe area, has addressed the quartzite-pile problem; later workers either have been unaware of it or have elected not to deal with it. Baldwin states (p. 78) that "the quartzite closely resembles Pennsylvanian sedimentary quartzite exposed northeast of Santa Fe; no other known rock in the areas bears any resemblance." The quartzite is lithologically very different from both the five ft (1.5 m) of Pennsylvanian siliceous sandstone to which he referred (p. 235), and the Pennsylvanian sandstones of the southern Sangre de Cristo Mountains described by Sutherland (Miller and others, 1963, p. 56-73). The problem is complicated further because the age of the La Tierra-Las Dos-subdivisions-area quartzite is yet to be established and may never be, inasmuch as quartz cannot be dated by either the fission-track or the K-Ar method, and the rocks are unfossiliferous.