JIm,
This is for you...
Tony, the key is Chick's use of the word "adaptation." It seems that he was saying that this was the "extremely narrowed entrance to a well-trapped green" portion of the design.
That article also mentioned other features borrowed from overseas. For example, "Another type is found on No. 5, which is a road hole taken from the famous St. Andrews..."
And "The short seventeenth, of Scottish Redan descent, is also interesting. The spacious green is on a plateau, diagonally from the tee, necessitating great accuracy of direction..."