He gives a description of what happened, as well as a detailed hypothesis on what he believed the 'Hairy Apes' to be.
Everyone knows that there are all sorts of concepts as to what these creatures really are.
Flesh and blood?
Something else?
It is not a view that I have not heard before, although the detail in which he describes his beliefs make it very interesting.
I will provide a link, but let it be known that it may take some time to read.
Just a bit of food for thought.
http://www.bigfootencounters.com/classics/beck.htm