| Geological formation|| Argentina|
El Tranquilo Formation Wikipedia
The El Tranquilo Formation is a geologic formation dating to roughly between 228 and 200 million years ago and covering part of the Late Triassic. The El Tranquilo Formation is found in the Santa Cruz province of Argentina. Purported fossils of the prosauropod dinosaur Massospondylus have been recovered from the El Tranquilo Sandstone.