David -
I would love to see anything people have, but my understanding is that there is little evidence about what the original Chasm Hole looked like. It didn't exist for very long.
Bob
If I understand the facts right...
* CBM's first Biarritz hole was at Piping Rock. Macdonald himself apparently gave it the name of Biarritz;
* There is no chasm on that hole at PR;
* The hole's outstanding feature is the swale in front of the green.
This makes me think the chasm hole in France had a similar green complex as the one at Piping Rock. i.e. both had a swale in front of the green. Otherwise, why would Macdonald name the hole at PR "Biarritz?"
Also, at Piping Rock, the Biarritz green did not include the swale or front tier. That suggest to me Macdonald did not base his Biarritz on N. Berwick's 16th. On top of that, 16 at NB is a par 4 (or even 5 back in the day?). If CBM had named the hole "Berwick" instead of "Biarritz", I'd have more confidence that 16 at NB was his model.
Even though the chasm hole in Biarritz no longer exists, the land features are still there. Could someone, if they wanted, take pictures, and then use photoshop to make some approximations of what the hole might have looked like?