Recently while visiting Sant Ignazio Roman Catholic Cathedral in Rome, Italy I found some ammonite fossils in the floor slabs. After researching on the Internet, there is a waymarking web site that documented this find. They are similar to the ones I found at St. Peter's Basilica in Rome.
The ammonite fossils are embedded in a number of red and yellow polished limestone slabs in the floor. The slabs are in the main floor of the church, the left side section of church with a statue, and the yellow stone on a crest toward the center floor of the church. They appear to be Rosso Ammonitico Lombardo (red polished limestone). This stone is dated to the Jurassic Period. I am not sure about the yellow stone, it might be Ammonitico Giallo. I hope to have a post about this in the near future.
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UPDATE (2022): These ammonoids could date to the Upper Jurassic Period of the Rosso
Ammonitico Formation, Oxfordian Stage, Verona Province, Venetia Region
of Italy. This iron enriched (red) limestone is also known as Red Verona Marble or Rosso Verona Marble.
