512 THE JOURNAL OF GEOLOGY. 



close these suggestions concerning limestone deposition by other 

 than organic means. 



Chemically deposited limestone is forming in the southern 

 part of Florida, probably over extensive areas. The Everglades, 

 4,000 to 5,000 square miles in extent, lie nearly at sea level, mar- 

 gined by barrier reefs which confine the surface waters ; in the 

 dry season the drainage consists of numerous small streams- — in 

 the wet season the region is all submerged save the numerous 

 muddy islands. Explorations on the western side, from Cape 

 Sable north to Punta Rasa, were made by Mr. Joseph Wilcox, 

 whose observations are stated by Dall as follows : T 



"At the north end of Lostman's Key (on the west coast, in 

 about latitude 25 ° 30') they entered the river of the same name 

 and succeeded in penetrating 12 or 15 miles inland. No hard 

 ground was seen except near- the mouth of the river, and the 

 highest land at the latter place was not over 3 feet above high 

 tide. Wide, shallow bays, with muddy bottom, interspersed with 

 low, muddy mangrove islets, comprise the scenery. The boat 

 frequently grounded, and was obliged to wait for the rise of the 

 tide. A small fresh-water stream was finally reached, the cur- 

 rent of which had scoured a channel 4 to 6 feet deep, with a 

 rough, hard, rock bottom, fragments of which were broken off. 

 It consisted of large masses of Po'lyzoa more or less completely 

 changed into crystalline limestone, the cavities filled with crys- 

 tals of calcspar. The rock is very hard and compact." 



"Allen's creek, emptying into Walaka inlet, an arm of Chuko- 

 liska bay, was also visited. At a point 8 or 10 miles east from 

 the Gulf of Mexico the party were able to land on soft, wet soil, 

 a little higher and drier than that at the head of Lostman's river. 

 A third of a mile eastward from the head of the creek specimens 

 were obtained of a few rocks which project above the soil. They 

 presented molds of recent shells with the interior filled with calc- 

 spar, and an occasional Pecten dislocates or Ostrea virginica, still 

 retaining its shell structure. The cavities between the shells 



1 Bull. U. S. G. S. No. 84. Correlation Essays — " Neocene," by Wm. H. Dall, pp. 99- 

 101 and 154. 



