S7. AMMONITE FOSSIL

Ammonites are an extinct group of marine animals. They are excellent fossils for indexing the age of the rock layer in which they are embedded. The closest living relatives today are, surprisingly, not the nautilus, but octopus, squid and cuttlefish.

Mathematically, it is clear that we have the recurrence of the equiangular spiral with its inherent self-similarity. This gives it a place in our gallery of fractals in nature.

http://en.wikipedia.org/wiki/Ammonite

http://commons.wikimedia.org/wiki/File:AmmoniteFossil.JPG