Wasatchian
The Wasatchian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology ( NALMA ) , typically set from 55 , 400 , 000 to 50 , 300 , 000 years BP lasting . 
<triplet> Wasatchian <subj> North American Land Mammal Ages <obj> instance of