125

 on the sample photographs at a larger scale suggest that

 ponds of one acre or less were not seen on the index sheet.

 A correction factor based on counts from the larger-scale

 photos was used to adjust these values to 8,560, 15,260,

 and 6,290 respectively, which gives a total of 30,110 ponds

 in the total three county area, and an average density of

 8.27 ponds/sq-mile (3.19 ponds/sq-km). The greatest pond

 density, 25 ponds/sq-mile (9.65 ponds/sq-km), was found in

 southwestern Hendry County in the area of the Okaloacooche

 Slough. Figure 24 is a copy of the acetate overlay used to

 count the ponds on the 1:250,000 Hurd index sheet.

 According to measurements from the sample photographs,

the average size of ponds in Hendry County is 11.1 acres

(4.5 ha) and the average size of ponds in Collier County is

7.99 acres (3.23 ha). Sixty-one percent of the ponds in

Hendry .County and 79% of the ponds in Collier County are

less than 10 acres (4.05 ha). Florida Department of

Natural Resources (1969) states that only 29 ponds in

Collier County are 10 acres or greater, which is at

variance with the results of this study. Methods of

measurement used by the Department of Natural Resources

were not published, so it was not possible to reconcile

their low figure with the results of the present study.

Histograms in Figure 25 illustrate the size frequency

distribution of ponds from the sample photographs in Hendry

and Collier counties.