238 



CARNEGIE INSTITUTION OF WASHINGTON. 



The immediate foundation of the Tertiary coral reefs and coraUiform beds 

 of every horizon in the southeastern United States is kno-vvn, except that of 

 the hving Florida barrier reef, through which no boring has been made, and 

 the general geologic history of the Floridian Plateau is now familiar.^ Without 

 exception, the reef corals have merely grown upon an antecedent basement 

 during or after subsidence and have played an unimportant role as construc- 

 tional agents. There are six important submarine banks or groups of banks on 

 the east side of Central and North America, as follows: Mosquito, Campeche, 

 Florida, and Georges banks, those off Nova Scotia, and the Grand Banks of 

 Newfoundland. They are all primarily of structural origin, and corals have 

 had little or nothing to do with their formation; but corals have grown and 

 still grow on the submerged surfaces of those which lie within the region where 

 conditions are favorable for the life of such organisms. 



Straiigraphic distribtUion of coral reefs and reef corals from Upper Oligocene to Recent time, and 

 their relation to changing sea-level. 



Series. 



Geologic formations, mem- 

 bers, and unconformities. 



Distribution of reef corals and 

 coral reefs. 



Change in relation of 

 basement to sea- 

 level. 



Recent .... 

 Pleistocene 

 Pliocene . . . 

 Miocene. . . 



Erosion unconformity. 



Erosion unconformity. 



Caloosahatchee 



Erosion unconformity? 



Coral reefs 



Coral reefs 



Reef corals 



No reefs, but some corals. 



Oligocene . . 



Eocene . 



Erosion unconformity. 



(Shoal River 

 Oak Grove. 

 Chipola. . . . 



Upper. . 



Lower . . 

 Erosion unconformity. 

 Ocala limestone 



Chattahoochee 



[A few corals; slight develop- 

 ment of reefs. 

 A few corals, one species of 



[ reef coral 



Coral reefs (Tampa, Fla.) 



Coral reefs (Bainbridge, Ga.). 



Subsidence. 

 Subsidence. 

 Subsidence. 

 Subsidence. 



Continued 

 subsidence. 



Subsidence. 



Note on the Electrical State in Leaves, hy J. C. Waller. 



The grounds at Tortugas offer excellent opportunity for studying the elec- 

 trical properties of leaves, under natural conditions, there being an abundant 

 supply of a monocotyledonous plant, Hymenocallis, growing around the lab- 

 oratory. The stiff leaves reach to a height of a meter or more, their bases 

 broadening into colorless scales which together form a storage bulb. A plant 

 transferred to a pot can, at will, be kept in darkness or exposed to the brilliant 

 sunlight of the semitropics. 



With the hope of making in the future a more exact study of the conditions 

 which influence the electrical properties of plants, I made some observations 

 on leaves, before and after exposure out of doors. 



The apparatus used was that of my father, Dr. A. D. Waller, and was sent 

 by him from England. He describes its use for the study of plants in "On 

 blaze currents in vegetable tissues" (Linn. Soc. Bot., vol. xxxvii, pp. 32-50). 

 In this paper he describes the electrical response to electrical excitation (which 



^Vaughan, T. W., A contribution to the geologic history of the Floridian Plateau. Carnegie 

 Inst. Wash. Pub. No. 1.33, pp. 99-185. 15 pis., 1910. 



Matson, G. C, and S. Sanford, Geology and ground waters of Florida, U. S. Geol. Surv. Water 

 Supply Paper 319, pp. 445, 17 pis., 1913. 



