Geology of Railroad Park

Railroad Reservation, designed as the hub of freight travel in the 1880s, sits in the Jones Valley on the lowest part of the Conasauga Formation, an extensive thin slab of limestone. Jones Valley rests below what was originally one of the tallest mountains in the region. Valley Creek emerges in this narrow section of the Birmingham valley, between the Cahaba Ridges geologic district to the southeast and the Warrior Basin geologic district to the northwest.

Topographic features of a region have an intimate relationship with how people use the land. Birmingham’s industrial birth depended on the accessibility of the region for railroads. Gaps in southernmost strands of the Appalachian Mountains provided a path for railroads north-south and east–west. The gaps through the ridges that define Jones Valley (Sand and Red Mountain to the north and south, respectively), such as Boyles Gap and Red Gap, have permitted the entrance of railroads to the heart of iron and steel manufacturing. Birmingham’s street grid also follows the lay of the land, which explains Railroad Park’s NW-SE orientation.

Because the Conasauga Formation is a karst formation, the limestone can fill up with water in wet years and dry down in droughts. This action, plus the subtle corrosion of the alkaline limestone by rain and groundwater’s slight acidity, causes holes to form in the rock. Under the right conditions, these can become sinkholes. Just a block from the park, the Birmingham Barons baseball stadium construction was delayed due to a sink hole over 100 feet deep at the entrance to the park. Filling these big holes and stabilizing the ground can be a challenge, but they are a fact of life given our geologic past.

Source: Charles Butts, Description of the Birmingham Quadrangle. U.S. Geological Survey. Geologic Atlas Folio 175, 24 pp., 1910