EXPLANATION OF PLATE 3. 
Fig. 1.—View in pit No. 5, Prairie Pebble Phosphate Company, Mulberry, 
showing overburden of land pebble phosphate. The contact between the light- 
colored incoherent sand and the somewhat indurated sand is well marked- The 
overburden in this pit is being removed by hydraulics. 
Fig. 2.—View in pit of Florida Mining Company, showing a place where 
the overburden beneath the superficial sand is indurated, making it necessary 
to resort to blasting. 
Fig. 3.—View in pit of the Pierce Phosphate Company, Pierce, Fla., showing 
an abrupt break in the pebble phosphate stratum. The break is seen near the 
right side of the picture, where slickensides have developed as the overburden 
slid down past the phosphate stratum. 
