• On the south side of Pico Salamanca much of the Rio Chico Formation is exposed, but neither top nor bottom contact was found by us. Starting at the shore there is about 30 meters of red (and in lesser part white and green) cross-bedded sandstone, apparently corresponding to the "middle member" of the Palangana section, and above this 20 meters or more of white to gray clay with lenses of white to pink sandstone. The upper part is obscured by slumped blocks of Patagonian. In the upper sandstone lenses of this upper pale clay series, and probably near the level of the most fossiliferous upper sandstone of the Bajo de la Palangana, mammals occur. We found a dasypod scute and an upper incisor of Notostylops or some related genus, in place at this level. On the bench at the base of the clif we found a lower premolar of Notostylops or a closely related genus and an upper molar of Oldfieldthomasia, but as these were not in place their evidence is not conclusive. The locality would repay more prolonged study than we were able to give it.