40741
However , molecular clock analysis of mitochondrial genes suggests a much older age for the crown group of cnidarians , estimated around , almost 200 million years before the Cambrian period as well as any fossils .
 location: Cambrian
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
 Entities: Cambrian 
Answer:
 location: Cambrian