David,
Am I reading too much into the characteristics of a Biarritz in thinking there is supposed to be a short (or down) side of the swale? #17 at Merion only has an incline, and only goes across half the green.
Jim, not sure I understand your question. Some of the similarities with the concept are the distance of the hole, the carry over the chasm (in this case the quarry,) the elevation change from tee to green (like the original hole,) and perhaps most importantly the playable "valley of sin" type swale immediately short of the hole. Merion legend has it that the swale was based on the Valley of Sin, but
Wilson had never seen the Valley of Sin when he built the hole. [Without digging back into my research I'm not certain, but I think that this was one of the greens which was rebuilt early because of drainage issues, but as near as I can tell from photos and descriptions, the large swale short of the green was always there, although it isn't clear whether it was then part of the green.]
Bahto has long contended that the swale on the Biarritz may actually be representative of the Valley of Sin, so the references in the Merion Legend to this being Merion's Valley of Sin certainly make sense. In the end we have a long par three (probably not even reachable for many at the time) over a quarry with a swale just short of the green that is presumably there so that one can run the ball up onto the green. Now normally one might think that this is just a coincidence, but given CBM's extensive involvement in planning the course and the fact that he chose the final layout plan, and given that this is a course with numerous holes and features utilizing CBM-type principles, it is hardly a stretch.
As for whether or not the similarities are exact, why would they be? CBM and/or Raynor didn't build the hole, and there was no model at NGLA for Wilson to try and approximate. Hugh Wilson built the hole, so it looks like a Hugh Wilson hole, not a Raynor hole. But conceptually, its a Biarritz, and may be closer to the original conception than many of the later ones by Seth.
Here is the photo posted by Jim Kennedy, above. Try to forget it is Merion. If you walked onto this hole on a CBM course, what hole would you think it was?