132 REPORTS OF INVESTIGATIONS AND PROJECTS. 



diately east of ^liami and extending to Key West. The following is a brief 

 statement of my observations : _ 



Nezv Cut, across the tongue or cape of the mainland east of Miami. — The 

 surface material consists of siliceous sands. 



Virginia Key.— The surface of this key, the first of the line of keys, is cov- 

 ered by siliceous sand, with some comminuted shells. 



Key Biscayne. — The surface of this key is also composed of siliceous sands 

 with some comminuted shells. 



Soldiers Key. — The summit and western side of this key are composed of 

 siliceous sands'. Coral-reef rock, composed of heads of Orbicella annularis, 

 O. cavernosa, Mccandra viridis, M. labyrinthiformis, and .1/. clivosa, outcrops 

 on the eastern side. 



Ragged and Sand keys, the next group to the south, were not examined, 

 but according to the observations of Prof. Louis Agassiz they are "formed 

 by coral boulders." 



' Elliott's Key. — The western side of the southern end of this key was ex- 

 amined just north of the entrance to Caesars Creek from the lower end of 

 Biscayne Bay. The maximum elevation of the surface at that place is esti- 

 mated to be 5 or 6 feet above sea-level. The surface is formed by coral-reef 

 rock with a very thin coating of soil. The corals observed were Dichoccenia 

 stokesi, Orbicella annularis, Mccandra labyrinthiformis, and Agaricia agari- 

 cites. 



Meigs Key, in Csesars Creek, between Elliott's and Old Rhodes keys, is 

 composed of coral-reef rock, elevated on its northern end about 4 feet. 



Old Rhodes Key. — Dr. Mayer visited this key and furnishes the following 

 note : He landed on the Hawk Channel side near the middle of the key, and 

 went about 100 feet inland, where he collected lithologic specimens of coral- 

 reef rock. He states that the surface is exactly the same as that of Elliott's 

 Key ; it is rough, with numerous potholes, calcareous mud, and elevated reef 

 corals. He collected specimens of Orbicella annularis and Mccandra viridis. 



On a previous trip along the Florida East Coast Railway I had an oppor- 

 tunity to examine railway cuttings from Key Largo to Knights Key, inclu- 

 sive. There are numerous exposures of elevated coral-reef rock along the 

 line of the railway. Mr. Samuel Sanford, wdio is preparing a report for the 

 U. S. Geological Survey on this portion of Florida, will present his observa- 

 tions in detail. 



Pigeon Key, off the lower end of Key Largo, in the Inner Passage, has a 

 surface composed of calcareous silt, with no reef corals exposed. 



Lignum Vitcc Key, north of the upper end of Lower Metacumbe, has a sur- 

 face composed of calcareous marl or mud. 



Baliia Honda Key. — No coral reef w^as observed exposed on the surface of 

 this key, the superficial material being loose calcareous sands. Dr. Mayer, 

 however, had observed on a previous occasion, remnants of an old coral reef. 



Big Pine Key. — The most westerly observed elevated coral reef rock was 

 at the southeastern extremity of this key. The reef rock occurs at water- 

 level, and extends beneath the water. Orbicella annularis, Favia fragum, 

 and Mccandra viridis were observed. As wash on the shore, probably from 

 the reef, specimens of Dichoccenia stokesi, Manicinia gyrosa, and Mceandra 

 labyrinthiformis were obtained. 



