On Friday, 26 June 2020 23:24:30 UTC+1, Dave Liquorice wrote:
On Fri, 26 Jun 2020 03:17:26 -0700 (PDT), polygonum_on_google wrote:

Have recently seen many small curved objects on the beach. They appear
to be just sand - pick one up and it breaks up into nothing but sand.
Therefore, I rather assume they are some sort of cast. Possibly some
sort of protein binding it all together.

Cerainly look constructed rather than just a cast. That plain edge on
the left of the close up, the patterning over the bulk. Are they
hollow? Could they be the "shells" of something akin to a cadis fly
larva?

Tried taking a deep spade full of sand with one on into a bucket and
seeing if some critter or shellfish can be found?

Just realised I had actually taken a picture from the hollow side:

https://www.dropbox.com/s/gcmc9que0e..._2212.jpg?dl=0