BULLETIN NO. 68


Figure 15. Diagnostic foraminifera in Hawthorn Group units. Upper left bar = 0.1 mm; upper
right bar = 1 mm; bottom row, bar = 0.5 mm.


Measured total porosity of 25 Arcadia
Formation samples averages 34.1 percent, with a
median value of 32.4 percent and a range from
12.4 percent to 54.5 percent.

 The updip limit of the unit occurs in northern
Pasco and Polk Counties where maximum
elevations exceed 90 ft (27.4 m) MSL (Plate 34
and 45). The top of the Arcadia Formation
occurs at depths exceeding -270 ft (-82.3 m)
MSL beneath the Lake Wales Ridge in the
southeastern part of the study area. The unit
ranges in thickness to greater than 750 ft (229
m) in south-central Charlotte County (Plate 46).
Sporadically throughout much of the central and
southern regions, the Arcadia Formation


(undifferentiated) is observed below the Tampa
and Nocatee Members. In several wells, the
contacts between the Tampa and Nocatee
Members and the underlying Arcadia Formation
(undifferentiated) are gradational. The Arcadia
Formation is unconformably overlain by the
Peace River Formation (where present);
however, apparent gradational contacts between
these two units are locally observed.

 In general, the Arcadia Formation comprises
the most permeable parts of the IAS/ICU in the
study area (see IAS/ICU, p. 57, for more details).
In addition, the uppermost part of the FAS is
comprised of the Tampa Member where it is in
hydraulic connection with the subjacent