Hall's Cave, TX Excavation (image) University of Houston Share Print E-Mail Caption Researchers relied upon isotope analysis of sediments collected from Hall's Cave, located in the Texas Hill Country, to determine a new explanation for a dramatic period of global cooling about 13,000 years ago. Credit M.R. Waters, Texas A&M University Usage Restrictions None Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.