"The existence of the fossil beds in the general area was known since the 1922 expedition of geologist Walter Shiller and paleontologist Santiago Roth. But the precise location was lost and remained unknown except to Dona Tica, who as a young girl had assisted the early expedition."
Now, now, it was probably her pet.
Well, originally she was assisting professional scientists with it. They probably kept some sort of records. How was she supposed to know that the precise location has been lost since 1922?