36 CHEMICAL MAXUEES. 



3 idle, and 3 in preparation. The total amount of rock phosphate 

 marketed in 1906 was 2,080,957 long tons, of a value of 8,597,437 

 dollars, against 1,947,190 long tons in 1905. The production of 

 Florida alone reached 62-1: per cent of the total production of the 

 United States. The exports of hard rock were 565,953 long 

 tons in 1906, against 595,491 long tons in 1905 ; they however exceed 

 those of previous years. The exports of land pebbles to America 

 and foreign ports, reached 482,232 long tons, against 385,915 

 in 1905. Eiver pebbles were not exported in the two last years. 

 The South Carolina output has continually decreased since 1893. 

 The production of Tennessee rose in 1906 to 528,888 long tons. 

 Tennessee phosphate occurs in three varieties, which are the blue 

 or black rock, the brown, and the white. The quantities marketed 

 in 1906 consisted of 93 per cent brown, 6-5 of blue, and 0*3 per 

 cent of white. In the west part of Putnam County, a new deposit 

 of blue rock phosphate has been discovered. This contained on an 

 average 65 to 75 per cent of tricalcic phosphate and only 5 per cent 

 of oxides of iron and alumina. Amongst the other phosphate 

 producing states, during the years 1901 to 1906, there may be 

 mentioned North Carolina, Pennsylvania, Arkansas, and Idaho. 

 But the production of these states was very low, except Idaho. 

 North Carolina produced 45 long tons in 1903, Pennsylvania 100 

 long tons in 1904. 



In Arkansas the production continually increases, though 

 slowly. Idaho promises to become a big producer of phosphates. 

 The bed, at a certain place, has a thickness of 85 feet ; the main bed 

 is 5 to 6 feet thick. 



X. Afeica. — Tunis and Algeria. — These two countries contain 

 enormous deposits of phosphates. As far back as 1873, Thomas 

 discovered the existence in the region south of the Tell, in the pro- 

 vince of Algeria, of a Suessonian formation, rich in phosphate of lime. 

 In 1886, the same geologist, after a scientific expedition, published 

 his first researches on the phosphate beds of the Eegency. He had, 

 more especially, examined the deposits in the neighbourhood of 

 Gafsa, in Tunis, showing their continuation through the South 

 Algerian region. The phosphate of these regions is found at the 

 bottom of the Eocene in contact with the Cretaceous, from which it 

 is separated unconformablv bv black muddv clavs of variable thick- 

 ness saturated with chloride of sodium and gypsum, with the 

 characters of silex. These j^hosphate beds consist of alternations 

 of marl and nodules of phosphatic limestones, covered in the south 

 of the Eegency by a bed of shelly limestone, which gives place to 

 a thick formation of nummulitic limestone as it ascends to the 

 north. The phosphate beds become at the same time more sandy 

 and glauconitic. 



Marly P]ios2)hate in Xodules, — The phosphate of hme occurs in 



