Numerous transects across Crescent Beach spring were conducted in 1994 to acquire HRSP of the subsurface. Two examples of the profiles are shown as A-A’ and B-B’. Unfortunately the navigational fixes attached to the digital seismic data have been lost, so horizontal scale of the profiles and their geographic location cannot be determined at this time. Another survey of the sink using Side-Scan Sonar, HRSP and a fathometer were done in 1998.

The seismic profiles (A-A’ and B-B’) show numerous strong, parallel reflections from about 30 m (98 ft) to 60 m (197 ft) below sea level. Gamma log profiles (Index Map H), interpreted from Gamma counts acquired from inland wells drilled within eight kilometers of the spring show numerous peaks in gamma counts at the base of the Hawthorn Group. These peaks are at similar depths to the strong reflections in the seismic profiles. The package of reflections highlighted by an orange background (A-A’ and B-B’) exhibits a slightly more “noisy” characteristic than adjoining reflections and may represent different lithologic or stratigraphic parameters. The series may correlate with the higher frequency gamma count peaks seen in gamma log profiles SJ0798 and SJ0171 between -21 m (-70 ft) and -30 m (-100 ft). Below 60 m (197 ft) the strong reflections diminish in the seismic profile (not shown). This change in acoustic return may represent the top of the Ocala Limestone. In the gamma profiles this surface is indicated by a blue line and ranges from an elevation of -53 m NGVD (71 ms or -170 ft) at SJ0151 to -69 m NGVD (92 ms or -220 ft) at SJ0162. Though there is insufficient data to confirm the identity of one reflecting horizon as the top of the Ocala Limestone, it is most likely around 70 ms (53 m, 174 ft) on the seismic data.