In northern Hudspeth County, Texas, a small cluster of low, predominantly silicic igneous outcrops known as Pump Station Hills is aligned within a row of subsilicic, alkaline intrusions. Tertiary age is generally accepted for the alkaline intrusions, but the age of the rocks at Pump Station Hills is uncertain. A complex of extrusive and intrusive rocks, including some not heretofore reported, has been revealed during the present petrographic study of the Pump Station Hills. The Tertiary intrusions on either side of Pump Station Hills and Precambrian igneous rocks from other parts of West Texas were studied briefly also and compared with the rocks in question. Granite porphyry, granophyre, and rhyolite found at Pump Station Hills are similar to the Precambrian rocks but th y do not resemble the rocks of the Tertiary intrusions. It is concluded that the rocks exposed at Pump Station Hills are Precambrian in age.