CORONADO’S TRAIL IN SOUTHWEST NEW MEXICO - page 2 of 4
The course of U.S. Highway 180, and New Mexico Highway 12 from Silver City, New Mexico to Reserve, New Mexico is of great interest to Coronado Trail studies, and there are some good reasons for believing that this same route was the one in use in pre-historic times. I propose that this was also a part of Coronado’s route in the year 1540.
The Mogollon Rim of Arizona divides the state into two parts, which are different physiographic provinces. This feature also extends several miles into New Mexico. North of the Rim is a part of the Colorado Plateau, and is an area of higher land elevations, while the area south of the Rim is a part of the Basin and Range province, with generally lower land elevations consisting of isolated mountain ranges and intervening desert basins.
Coronado was seeking a route for his travel to the north, and the best existing trail route to Zuni at that time was the same route now shown as U.S. Highway 180 on modern maps. The feasibility of this route is determined by the local geography and geology. The route follows a major structural trend that was named by Fred Trauger, professional hydrologist, in 1972. He named this broad valley the “Mangas Trench”. Following Mr. Trauger’s work, in 1981 Dr. Wolfgang Elston provided a geologic sketch map of the Mangas Trench which is used by permission here.
The Mangas Trench is described as a NW trending geologic structural feature bounded on the east by a fault zone in the Silver City mountains, and bounded on the west by the uplift of the Burro Mountains. The net effect of this feature is a wide valley between the mountains that provides a better road to the northwest following the geography of the land. This is the same general route now followed by Highway 180.
The structure of the Mangas Trench was previously referred to as the Mangas Graben, meaning that as the adjacent mountains rose, a large block of rock also dropped, forming a valley. This situation also is noticed to the south and west of Reserve, New Mexico, where a similar fault block has dropped to form the Reserve Graben, which also forms a valley on the surface of the land. The valley formed by the Reserve Graben intersects with the valley formed by the Mangas Trench, continuing the optimum trail route to the north and east through these connecting valleys. Therefore I suggest that the geography of the land has produced and determined the best trail route through the Mogollon mountains of southern New Mexico.
