142 Papers from the Marine Biological Laboratory at Tortugas. 



EFFECT OF THE FLORIDA COUNTERCURRENT ON THE SHORE TOPOGRAPHY OF 



FLORIDA. 



When a map of the east coast is examined, its long sweep and gentle 

 curves are immediately observed; there are no prominent salients or 

 deep indentations, no small irregularities, and for miles the shore-Hne 

 may be almost straight. Several other features are to be correlated with 

 the alongshore current. 



(i) Elongated sounds called rivers paralleling and lying near the 

 coast: north of St. Augustine are Tolomato or North River and Guano 

 River, both of which empty to the southward, and south of that city is 

 the Matanzas River which empties to the northward, the three finding an 

 exit to the ocean through St. Augustine Inlet (fig. 5). The Matanzas River 

 has a smaller inlet from the sea at its southern end. Follovv'ing the coast 

 southward, Halifax and Hillsboro rivers are in communication with the 

 ocean through Mosquito Inlet. The latter "river" connects at its south- 

 em end with Mosquito Lagoon, which is just north of Cape Canaveral. 

 Back of this cape and of the beach to the south of it is Banana River, 

 which is barely separated from the northern portion of Indian River. 

 In fact, Mosquito Lagoon, Banana River, and Indian River are all more 

 or less in communication through Banana Creek, which forms an irregu- 

 lar, sinuous northern boundary of Merritt Island. Indian River is suc- 

 ceeded to the southward by Hobe and Jupiter sounds and Lake Worth. 

 Between Hillsboro Inlet and the northern end of Biscayne Bay are 

 several small lagoons and salt-water creeks. 



(2) The beaches and islands along shore have their southern ends 

 elongated, often pointed, while their northern ends are wider and fre- 

 quently more or less truncated. Amelia Island, on which Femandina is 

 situated (fig. 4), is an instance of such an island with a truncated northern 

 end. Anastasia Island, on the south side of St. Augustine Inlet, is 

 another instance, but its northern end is not so obtuse as that of Amelia 

 Island (fig. 5). 



(3) Southward Deflection of Stream-mouths. — Two good instances 

 of this phenomenon are seen in the vicinity of Fernandina (fig. 4). To 

 the north of Anastasia Island is Cumberland Sound, through which St. 

 Mary's River empties into the ocean; to the south is Nassau Sound, 

 through which Nassau River flows. Both of these sounds are directed 

 from the northwest to the southeast. New and Middle rivers, the streams 

 next north of the upper end of Biscayne Bay, have their mouths deflected 

 southward. The phenomenon is general along the Florida east coast. 



(4) Overlaps and Offsets.^ — -Instances of both these phenomena are 

 present and can be seen in the vicinity of St. Augustine (fig. 5) . The point 

 of land north of St. Augustine Inlet overlaps the northern end of Anas- 

 tasia Island; overlap and offset are necessary accompaniments of the 

 kind of stream deflection exhibited along this coast. 



(5) Current Cuspate Forelands. — Gulliver has cited Cape Canaveral 

 as an almost typical example of this shore form (fig. 6).^ 



' Gulliver, Shore-line Topography, Proc. Amer. Acad., vol. xxxiv, 1899, p. 178. 

 ^ Proc. Amer. Acad., vol. xxxiv, p. 180, fig. 10. 



