Picture A Day October 12, 2009 - The Mouth of Presa Canyon
At the junction where Seminole Canyon merges with Presa Canyon at the end of the Pressa Trail in Seminole Canyon State Park. Two miles in the opposite direction is the Rio Grande and Mexico, and this marks the edge of Lake Amistad, the arm of Presa Canyon veering to the right is dry. The canyon walls are between 100 and 200 feet down to the water's edge below, with plenty of sheer drops, making access to the water a near impossibility. The slow process of weathering in the desert cracks the rock walls, with large chunks breaking away every once in a great while (like the precariously perched rock to the left). The exposed limestone rock turns dark from oxidation ('desert varnish'), the recently uncovered rock faces remain a light tan. In the protected undersides of the ledges along the canyons, some of the oldest pictographs in America can be found, marking nearly ten millenia of human habitation in the region.
You can view more photos from my 2009 'Picture a Day' set at: www.flickr.com/photos/matthigh/sets/72157625855768121/
And the fun continues with a Picture a Day through 2010 at: www.flickr.com/photos/matthigh/sets/72157620610035860/