300 Scientific Intelligence. 



2. The Phosphate Deposits of Florida ; by G. C. Matson. 

 U. S. G. S., Bull. 604, 1915, pp. 99, 17 plates and geologic map. — 

 Shortly after the " Pebble Phosphates of Florida " by E. H. Sel- 

 lards made its appearanee, another paper on Florida phosphate 

 deposits, by G. C. Matson, was received. This paper is a com- 

 prehensive treatise of the different kinds of phosphate deposits of 

 Florida, while tbe former deals with the pebble-phosphates. 



The geology of Florida is described in considerable detail and 

 correlations made between formations in different parts of the 

 state. Detailed descriptions and discussions of the mode of 

 occurrence of the phosphate deposits of the individual districts is 

 given. The hard-rock, pebble-phosphates and river-pebble phos- 

 phates, are all described and discussed and a review of the litera- 

 ture is made concerning the origin of these different types of 

 phosphate deposits. 



The rock-phosphates occur in the Vicksburg ground of lower 

 Oligocene age and in the Bluff Alum formation of upper Oligo- 

 cene Age. They consist of bowlders and pebbles enclosed in a 

 matrix of soft phosphate and clay. Those of the Vicksburg 

 group have in part been formed in place by alteration of calcium 

 carbonate to calcium phosphate under the influence of solutions 

 bearing phosphoric acid, and in part by the erosion and redeposi- 

 tion of pre-existing phosphate. For the origin of the phosphoric 

 acid of the Vicksburg group three theories are considered : that 

 of original phosphate in the limestone, phosphate derived from 

 organic matter and phosphate derived from the overlying Alum 

 Bluff formation. The latter is considered the most probable. 

 The rock-phosphate of the Alum Bluff formation is believed to be 

 marine phosphate. 



The land-pebble phosphate of the Bone Valley formation is 

 thought to have been derived from the underlying formation by 

 erosion and deposited as a phosphate conglomerate during the 

 late Miocene or early Pleiocene incursion of the sea. The varia- 

 tion in size and phosphoric acid content of the deposits is con- 

 sidered to be due to local concentration or dissipation of the peb- 

 bles in the process of water sorting. 



The river-pebble phosphates are considered to be of fluviatile 

 origin and derived by rivers of Pleistocene and Recent age work- 

 ing over the Bone Valley formation. 



This paper presents the most complete data we have concerning 

 the occurrence and origin of the Florida phosphate deposits and 

 the theories of origin are of wide application. Views held by 

 previous writers have been reviewed, and a complete bibliography 

 of Florida phosphates lends additional value to the report. 



A. M. BATEMAN. 



3. A Correction; by F. Bascom {Communicated).— Shortly 

 after the publication of a paper on the Petrographic Province of 

 Neponset Valley, Massachusetts,* Dr. Whitman Cross very kindly 



*Bascona, F., Journal of the Academy of Natural Sciences of Philadelphia, 

 Second Series, vol. xv, pp. 131-161, 1912. 



