Pleistocene rocks in El Paso and Hudspeth Counties, Texas adjacent to Interstate Highway 10
— W. S. Strain

Pleistocene rocks are exposed in the Rio Grande Valley in El Paso and Hudspeth Counties. Interstate Highway 10 follows the Rio Grande Valley paralleling the river from the northern border of El Paso County to the Quitman Mountains in Hudspeth County. From the New Mexico-Texas state line to El Paso, the highway lies in the Mesilla Bolson. From El Paso to the Quitman Mountains, the highway passes through the Hueco Bolson.

Pleistocene rocks crop out locally adjacent to Interstate 10. Near the Quitman Mountains the river and highway diverge. The highway veers to the north of the Quitmans and the Rio Grande passes through a narrow gap south of the mountains at which point it enters the Red Light Bolson.

Four formations have been described in the three bolsons. The Fort Hancock and Camp Rice formations occur in the Mesilla and Hueco bolsons. The Bramblett and Love formations are restricted to the Red Light Bolson. The deposits are poorly consolidated and are of fluvial and lacustrine origin. The Fort Hancock is older than the Camp Rice Formation, and the Bramblett Formation is older than the Love Formation. Lithologically the Bramblett is very similar to the Fort Hancock and the Camp Rice resembles the Love Formation. Most of the strata are essentially horizontal. The Fort Hancock and the Camp Rice formations are included in the Santa Fe Group (Kottlowski and LeMone, 1969).