The Geology of Shiloh National Military Park: Cretaceous Shorelines and River Terraces

Shiloh National Military Park has two parts: the Shiloh Battlefield, on the west bank of the Tennessee River in Hardin County, Tennessee, and the Corinth Unit at Corinth, Mississippi. Established on December 27, 1894, the park covers about 2,719 hectares (6,720 acres) and preserves battlefields, sites and resources tied to Shiloh and Corinth in the Civil War's Western Campaign.

Two battles

The Battle of Shiloh, fought in April 1862, was a major struggle for control of the western Confederate railroads and the Mississippi River Valley, and it ended in a decisive Union victory. Six months later, in October 1862, Confederate troops tried to drive Union forces out of their fortified defenses at Corinth and were defeated again — the last major Confederate offensive in Mississippi. The Corinth Unit protects a few surviving early earthen fortifications, forerunners of the trench warfare that would define the war's final year.

A replica of Shiloh Church, on the original site. Image from the National Park Service's page.

The ground beneath the battlefield

The park's geology records a long history of deposition, several rises and falls in sea level, and the development of the Tennessee River valley.

• Bedrock: every rock unit under the park is Cretaceous sedimentary rock, laid down in nearshore settings along the upland edge of western Tennessee.
• Eutaw Formation: the oldest unit mapped in the park — marine sands and clays.
• Coffee Formation: above the Eutaw — sands and clays deposited in lagoons, on barrier bars and along shorelines.
• River deposits: early versions of the Tennessee River reworked the Cretaceous layers, cutting channels and laying down thick beds of gravel, sand, silt and clay in the Quaternary. Many were left behind as raised, cut-up terraces, one of them "Shiloh Hill."
• Alluvium: the youngest units are loose Quaternary sediments along the Tennessee River and its floodplains.

The park lies in the Coastal Plain physiographic province, and shares its geologic history and several of its formations with a region reaching far beyond its boundaries.

Part of the park's digital geologic map. National Park Service, Geologic Resources Inventory.

Maps and reports

The park's geology is documented by the NPS Geologic Resources Inventory, which makes digital geologic maps and reports for more than 270 natural resource parks. For Shiloh these include a scoping summary, a digital geologic map, a report and a poster. A soil survey by the NPS Soil Resources Inventory has also been completed. All are available through the NPS DataStore.

Sources

• National Park Service: "NPS Geodiversity Atlas—Shiloh National Military Park, Tennessee and Mississippi," citing Thornberry-Ehrlich (2018) and National Park Service park documents (2016).