3i8 IN LOWER FLORIDA IVILD'S 



The plateau is named after Count L. F. Pour- 

 tales who discovered it many years ago and by his 

 dredging operations upon it has made it a classical 

 ground to naturalists. In the Hawk Channel the 

 water is more or less protected by the outer reef; 

 the bottom is usually soft and supports in certain 

 locaUties a rich and abundant marine fauna. 

 The foundation of the plateau, on the other hand, 

 is a recent limestone built of remains of the count- 

 less marine organisms that have lived upon it. 

 Throughout the floor is an uneven compUcated 

 surface and it fairly swarms with life. It is, how- 

 ever, so very rough and broken that all dredging 

 over it is most difficult. 



The EoUs has a large cockpit aft which contains 

 the sounding and hoiisting machinery, and in it 

 the dredged material is sifted, washed, and as- 

 sorted. The dredges we use consist of two strong, 

 parallel steel blades, either of which may scrape 

 the bottom, and these are held in place by two 

 heavy bars or standards, so that the whole forms a 

 frame seven or eight inches wide and thirty inches 

 to four feet long. The front parts of the blades 

 are hammered to an edge in order better to scrape 

 the bottom; a row of holes is punched along their 



