Texas National Natural Landmarks: A Survey of Geological and Biological Wonders
Texas is a state of immense geographical diversity, ranging from the humid coastal prairies of the Gulf to the arid high plains of the Panhandle. To preserve this heritage, the United States has designated 21 National Natural Landmarks (NNLs) across the state. These sites are recognized for containing outstanding biological and geological resources that illustrate the natural history of the region.
From ancient dinosaur tracks to complex subterranean cavern systems, these landmarks provide a window into the prehistoric and environmental forces that shaped the Lone Star State.
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Key Facts
- There are 21 designated National Natural Landmarks in Texas.
- Landmarks are managed by a variety of entities, including federal agencies, state departments, municipal governments, and private owners.
- The sites cover diverse ecosystems, including the Gulf Coastal Plain, the Edwards Plateau, and the Great Plains.
- Notable features include the only known source of full-grown sauropod footprints and multiple meteorite impact craters.
Geological Marvels and Caverns
Texas is renowned for its subterranean landscapes. Several NNLs highlight the state's unique karst topography—landscapes formed from the dissolution of soluble rocks such as limestone.
Subterranean Systems
The Caverns of Sonora and Natural Bridge Caverns are prime examples of the state's cave diversity. The former is noted for bladed helictites and coralloid growths, while the latter features a multilevel system with intricate speleothems (mineral deposits formed in caves). Other significant sites include Longhorn Cavern, which showcases features from the phreatic phase (the stage where a cave is completely filled with water), and the Cave Without a Name, recognized for its rare speleothems.
Surface Formations and Impact Sites
Beyond the caves, Texas hosts dramatic surface features. Enchanted Rock serves as a classic illustration of a batholith—a large mass of intrusive igneous rock—and the process of exfoliation. The Devil's Sinkhole provides a stark example of a collapsed limestone sink, while the Odessa Meteor Crater contains two impact craters, the largest measuring 550 feet (170 m) in diameter.
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Biological Diversity and Habitats
The biological landmarks of Texas protect critical habitats that support rare species and represent the state's varied ecological zones.
Coastal and Riparian Zones
Along the coast, the Attwater Prairie Chicken Preserve protects a significant segment of gulf coastal prairie. In the western Gulf Coastal Plain, Catfish Creek remains one of the few undisturbed riparian habitats (areas situated on the banks of a river). The Bayside Resaca Area, located within the Laguna Atascosa National Wildlife Refuge, preserves a resaca—a channel formed by a cut-off river.
Plains and Plateaus
The High Plains Natural Area and Muleshoe National Wildlife Refuge preserve the shortgrass climax communities of the Great Plains. In the hill country, the Lost Maples State Natural Area and Little Blanco River Bluff illustrate the unique flora and fauna of the Edwards Plateau.
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Paleontological Significance
Texas offers a rich record of prehistoric life. Dinosaur Valley State Park is globally significant as the only known source of distinct, full-grown sauropod footprints. Additionally, Greenwood Canyon serves as a vital resource for early Cretaceous mammalian fossils.
Summary of Texas National Natural Landmarks
| Landmark Name | Year Designated | County | Ownership | Primary Significance |
|---|---|---|---|---|
| Dinosaur Valley State Park | 1968 | Somervell | State | Sauropod footprints |
| Odessa Meteor Crater | 1965 | Ector | County | Meteorite impact craters |
| Enchanted Rock | 1971 | Gillespie, Llano | State | Batholith and exfoliation |
| Palo Duro Canyon State Park | 1976 | Armstrong, Randall | State | Water-created landform |
| Santa Ana National Wildlife Refuge | 1966 | Hidalgo | Federal | Lowland forested area |
Frequently Asked Questions
How many National Natural Landmarks are in Texas?
There are 21 designated National Natural Landmarks located throughout the state of Texas.
Which Texas landmark is famous for dinosaur tracks?
Dinosaur Valley State Park is the only known source of distinct and full-grown sauropod footprints.
What is a resaca, and where can it be found?
A resaca is a specific type of waterway found in the Bayside Resaca Area within the Laguna Atascosa National Wildlife Refuge.
Who owns the National Natural Landmarks in Texas?
Ownership is diverse, spanning federal agencies (such as the US Fish & Wildlife Service), state agencies (Texas Department of Parks and Wildlife), municipal governments (City of Fort Worth), county governments, and private owners.
What makes the Odessa Meteor Crater unique?
It contains two meteorite impact craters, with the largest measuring 550 feet (170 m) in diameter.