Zheng He in America

Menzie does make some compellling arguments about China discovering the Americas. The accuracy of the maps of the two islands serves as such an important piece of evidence suggesting Chinese arrival. Menzie was fascinated that they even got the three bays down. However, on the next island over with the volcano, the old map has a clear depiction of a bay, but the modern map shows no bay in that same location. I fail to see how Menzie can accept a false placement of a bay and accept three correct ones, unless volcanic eruptions filled in the bay. 

Stones in a peculier arrangement points to an idea that a civilization has come and gone. I don't see why Menzie thinks that it had to have been a Chinese civilization. People have been in America before the arrival of people from ships from the eastern hemisphere, and they could have made those stones. Also, I don't see why an armada of ships would stop to build shelter and then go back to the waters.