THE IRRIGATION OF CITRUS GROVES. 323 



Terra Ceia (6), as well as at the points already mentioned 

 and many others not indicated on the map. One of these 

 wells is shown in Fig. 74. 



While the surface of Florida is remarkably flat to 

 the eye and such elevations as do occur are not strongly 

 marked, there are two main anticlinal folds, the higher 



Fig 1 . 71. Elevations and depressions in Florida, between Tampa and 

 Titusville. (From Rep. TT. S. G. Survey.) 



one passing through Jasper, Lake City, Gainesville, 

 Brooksville, Lakeland, Bartow, Fort Meade, Arcadia and 

 gradually disappearing at the southern end of the penin- 

 sula. Some points upon the crest of the other are Mac- 

 clenny, Lawtey, Starke, Hampton, Interlachen, Summit, 

 Highland, Orlando and Narcoose. It may be noted here 

 that some of the points on these ridges, as Brooksville, 

 Lake City and Highland, are more than 200 feet above 

 sea level, while many of the points in the syncline or 

 valley between the two folds, as well as points on either 

 coast are but a few feet above sea level. These folds give 

 plenty of head for the downward flow of water. Fig. 

 71, which represents a section of the State from Tampa 

 to Titusville, illustrates this point. 



The artesian wells are made possible by the collec- 

 tion of water in an inclined pervious layer of rock which 

 lies between two impervious layers. Water collects in 

 this layer under pressure and when wells are drilled into 

 it, it rushes upward, reaching nearly the same level as 



