Can You Identify These seashell (fossil)?

[brambio]

Found it in Indrayanti Beach Yogyakarta, Indonesia about 2 days ago.
Can you help me to identify these seashell fossil?

Fossil 1:


Fossil 2:


Many thanks for your help.

Sincerely,
Bram

[paul monfils]

These are not fossils. This is Magilus antiquatus, a strange species in the family Coralliophilidae, which bores in coral.  The juvenile shell looks like a typical little snail, as in the upper image; but as it grows it loses its spiral form and takes the form of a heavy tube, as in the lower image.  Also, as it grows, it completely fills in the interior of the shell with shell material, first the spiral portion, and then successive portions of the tubular part, which is why they look like fossils.

[brambio]

Thanks for the info Paul . I get some good info about the species.
If I search Google images, I got more result for keyword "Magilus antiquus" than "Magilus antiquatus".

[dave r]

Antiquus is the correct name:
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Dave