Simplify the following text for a Grade 8 native English-speaking person.
Original: It is through his book that the cliff dwellings of Mesa Verde became known and his volume might well be called the harbinger of Mesa Verde National Park as we know it today .
Simplified: The Spanish term Mesa Verde translates into English as `` green table . '' Approximately 600 of the over 4700 archeological sites found in Mesa Verde National Park are cliff dwellings .