The Precambrian rocks of Texas are composed of igneous and metamorphic
rocks and some sedimentary rocks. Most of the Precambrian outcrops are
in the Llano uplift and El Paso and Van Horn regions.
Alterations produced by vast amounts of time, heat, and pressure have
obliterated any trace of fossils that may have been present in these
rocks. With the exception of some questionable primitive plants
collected in the Van Horn region, no Precambrian fossils have been
reported from Texas.