Continuing southeast about six kilometers from Río Hondo  along Highway CA-10 (the junction is at Km. 135), the first town you’ll come across is Estanzuela. The terrain here is decidedly dry, resembling parts of Arizona, making for an excellent environment for the preservation of fossils.
Sure enough, you can see some dinosaur bones, including the skeleton of a 50,000-year-old mastodon and that of a prehistoric whale at Museo de Paleontología Bryan Patterson (tel. 7941-4981, 9 a.m.–5 p.m. daily, free admission).
To get here, go through the town and follow the blue signs to the museo.