Editing Groesbeck, Texas (section)

=== Discovery of oil and natural gas ===

In 1912, natural gas was discovered in the Mexia-Groesbeck area, and it was soon speculated that it may be possible to also find oil in the area. In October 1920, Col. A.E. Humphreys completed an oil well began by the Mexia Oil and Gas Company and discovered oil at a depth of 3100 feet.<ref name="auto">https://scholar.smu.edu/cgi/viewcontent.cgi?article=1007&context=fondrenscienceseries</ref> A proper well was set up and producing 4000 barrels a day by the summer of 1921. The discovery was notable because it was the first discovery of oil fields formed by the [[Cenomanian]]-era [[Woodbine Group]] geologic formation. This encouraged future exploration in the Woodbine sand, leading to the discovery of many other Woodbine fields, including the giant [[East Texas Oil Field]], which was discovered in 1930.<ref name="auto"/> By January 1922, $5 million had been invested in Mexia and 5 million barrels of oil had been extracted. On January 12, martial law was declared for the second time in Limestone county history due to:
:Open and flagrant violation of the law, highway robberies, open gambling and selling of liquor.<ref name="auto1">{{Cite web|url=https://archive.org/details/texasoilgassince0000warn/page/70/mode/2up?q=mexia|title=Texas oil & gas since 1543|first=C. A. (Charles Albert)|last=Warner|date=April 14, 2007|publisher=[Rockport, Tex.?] : Copano Bay Press|via=Internet Archive}}</ref> 
The oil discovery brought wealth to the area, but in Groesbeck natural gas was more commonly extracted due to the lack of suitable oil deposits.<ref>{{Cite web|url=https://archive.org/details/texasoilgassince0000warn/page/156/mode/2up?q=mexia|title=Texas oil & gas since 1543|first=C. A. (Charles Albert)|last=Warner|date=April 14, 2007|publisher=[Rockport, Tex.?] : Copano Bay Press|via=Internet Archive}}</ref> After 1922 however, production of oil and natural gas declined rapidly.<ref name="auto1"/><ref>{{Cite web|url=https://www.hmdb.org/m.asp?m=145207|title=Mexia Oil Boom Historical Marker|website=www.hmdb.org}}</ref> By 1927 most of the heavy oil extraction was finished in Limestone county, but the formations remain useful for [[Paleobiology|paleobiologists]].<ref>{{Cite web|url=https://gsa.confex.com/gsa/2017SC/webprogram/Paper289203.html|title=Abstract: NEW DATA ON MID- CRETACEOUS ECOSYSTEMS AND FAUNAL DIVERSITY IN APPALACHIA: INSIGHTS FROM THE WOODBINE FORMATION (CENOMANIAN) OF NORTH TEXAS (South-Central Section - 51st Annual Meeting - 2017)|website=gsa.confex.com}}</ref><ref>{{Cite journal|url=https://swco-ir.tdl.org/collections/756f9a9d-302f-433c-8b28-6410713ba27b|title=1920-1996, Mexia Oil Boom|via=swco-ir.tdl.org}}</ref>

The oil boom led to many [[Truss|trusses]] being built in the area. This type of bridge, popular among Texans in the early 20th century, is a rare sight now. Seven trusses, all built in the 1920s, survive in their original locations in Limestone county as of 2025.<ref>https://www.limestonechc.com/historic-bridges/</ref>