Read the text and determine if the sentence is true:

The Portezuelo Formation is a geologic formation outcropping in the Mendoza, Rio Negro and Neuquen provinces of Argentina. It is the fourth-oldest formation in the Neuquen Group and the older of the two formations in the Rio Neuquen Subgroup. Formerly, that subgroup was treated as a formation, and the Portezuelo Formation was known as the Portezuelo Member.

Sentence: Portezuelo Formation wasn't known as the Portezuelo Member
No