In Texas mountains: Clues to ancient sea levels
Rocks from the fossil Permian Reef reveal secrets from 265 million years ago
http://www.msnbc.msn.com/id/44147979/ns/technology_and_science-science/#.TkpQc2Ax2Qg
"The ancient reef grew in water just below sea level and it overlooked the Permian Basin, which was more than 1,000 feet deep," said study author Thomas Olszewski of Texas A&M in College Station. "The rocks at the foot of the mountains preserve sediments that record natural environmental changes caused by changing sea level and climate."
These valuable rocks can show a record of past events in Earth history, and in the Permian Reef geologists can clearly see evidence for numerous rises and falls of sea level, Olszewski said.