Corals
http://www.museum.vic.gov.au/prehistoric/time/corals.html
http://www.oum.ox.ac.uk/thezone/fossils/inverts/coral.htm

http://www.seaworld.org/animal-info/info-books/coral/

http://www.42explore.com/reef.htm
http://geology.er.usgs.gov/paleo/corals.shtml