If the shingle is a coastal beach then the tags should be changed to:
Chatham Islands Uploaded: 6/5 --Glen
+ surface=shingle ?
RP: a beach is a cultural concept, not related to the physical composition, and not specific to shingle. i would be wary of using beach here (i should change my opinion on the natural=sand page too). i think we should create natural=shingle. surface= is only relevant for roads and similar
HB: beach is interface between land and water, I just mentioned it because it was the only OSM wiki page with the word "shingle" in it :). shingle in this context is most likely to occur along a braided river. Hmm, I wonder how shingle is different from scree once you are no longer on a mountain?
Glen: Note that the tags below should be used by default however for Chathams I changed the tags in JOSM to be natural=beach, surface=shingle as the polygons were on the coast (ie. a beach)
HB 19 Aug 2012: uploaded for the Antipodes Isls. in changeset 12780057. The situation was the same as for the Chathams, so I manually retagged as beach+surface as above. The LINZ data def'n has a braided river as the example, so keeping tagging as-is for the mainland.
Glen wrote on the ML: OK by me. Just add some uploader notes at the top of the comments. [see above]
2012-09-18: Tagging approved.