9561
The staff collected and cataloged tens of thousands of fossils , including many Cretaceous mosasaurs , Pleistocene ground sloths , and primitive Eocene archaeocete whales .
 Cretaceous, Pleistocene, Eocene
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Cretaceous, Pleistocene, Eocene