When I visited Savannah, Georgia USA in August 2017, found this interesting oyster concrete sidewalk. This sidewalk was at the corner of 300 Habersham St. and 321 E Liberty St. According to a 2017 report on historic pavement in Savannah Georgia, some sections of the city have "1950s Concrete with oyster shell aggregate". This sidewalk might be one of these sections.
I don't think these shells are fossils though maybe one day they will be. This concrete is an interesting way to use shells though and thought it might be worth noting.
Read report at this site:
http://savannahga.gov/DocumentCenter/View/10017/Report-on-Historic-Pavement-in-Savannah_v3?bidId=
See map of city with areas marked here:
http://www.historicpavement.com/savannah
