88819
Lava strata are most easily seen at the Grand Canyon of the Yellowstone , where the Yellowstone River continues to carve into the ancient lava flows .
 Grand Canyon of the Yellowstone, Yellowstone River
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Grand Canyon of the Yellowstone, Yellowstone River