Figure 8. Photo shows cross section of a massive Montastrea annularis skeleton exposed in the man-made Key Largo Waterway (also called Adams Cut) through the Key Largo Limestone on Key Largo (upper Keys). The Key Largo Waterway connects Blackwater and Largo Sounds (Fig. 6A). Compare with live specimens in Figures 3B, 3D, 4A, and 4H. The coral in this photo grew on an unconformity (approximate location of white line at bottom). The top of the reef is 4 m above sea level at this site. To sample the specimen for x-ray analysis, four areas of the surface were coated in epoxy resin and cut with a power saw to remove V-shaped coral 'cores' (red dotted lines; the "V" points into the coral). Counting of annual growth bands in x-radiographs indicated the coral was 360 years old (Hudson, 1979).