Garner State Park, Frio River. (Texas State Parks need our help. Visit a Texas State Park near you.) - About 145 million years ago, during the Cretaceous era, this part of Texas was covered by shallows seas, which lay down the shale and limestone formations in the area. Throughout the park, the river is lined with Bald Cypress trees, the only deciduous conifer in North America. In the autumn, the cypresses turn a rusty orange, forming a brilliant contrast to the famously turquoise waters of the Rio Frio.