i8 9 5. NOTES AND COMMENTS. 153 



Holland points out, that attractive mineral seems connected with the 

 junction of peridotites and carbonaceous rocks. We believe, how- 

 ever, that at Kimberley the diamonds are still forthcoming, although 

 the neck of ultra-basic rock has been worked down into the granite 

 that underlies the shales. No diamonds have yet been found in 

 connection with the Indian peridotites, so that their interest is for 

 the present somewhat esoteric. Even the large quantity of phosphoric 

 acid, present in the form of apatite, is not enough to render the rock 

 of economic value. Not only does the apatite withstand decomposi- 

 tion longer than all the other constituents of the rock, with the excep- 

 tion of the biotite, but "even the richest form would be poor com- 

 pared with the basic Bessemer slags, and the use of these has been 

 attended with indifferent success." 



Fortunately, the world has as yet no need for a fresh source of the 

 fertilising phosphates. From the Revue Scientifique we learn that a 

 wide band of phosphate of lime, 70 or 80 kilometres in length, runs 

 right through Algeria and extends into Tunis. Its richness is 

 remarkable, and the supply is enough to furnish the whole of Algeria 

 and Europe into the bargain. At Tebessa, not far from the frontier 

 of Tunis, the phosphate is already being worked, and it is estimated 

 that there are in the quarries a hundred million tons of this precious 

 food for cereals. France is to be congratulated. But, alas ! even 

 here she is not safe from the perfidious and enterprising Albion. Of 

 the three concessions at Tebessa, two are already in the hands of 

 British companies, who pay a royalty of only 50 centimes per ton. 

 As the market price of the phosphate is 40 francs a ton, it can be sold 

 on the London market at a profit of more than 20 francs per ton. 

 Here is a grand opening for the Socialists to spring another attack on 

 the President of the Republic, and to furnish the papers once more 

 with the familiar headline, " A Scene in the Chamber." 



But we must return from the stormy seas of politics and commerce 

 to calm scientific contemplation of phosphates. France has yet other 

 phosphates, and among them some of the most remarkable are found 

 in pockets in the great limestone plateau that stretches from Uzes to 

 the neighbourhood of the Rhone opposite Avignon. The limestone 

 is of Lower Cretaceous age, being that which is called Urgonian, 

 from the town of Orgon, near Aries. The pockets of phosphate of 

 lime are of two kinds. In the first type the Urgonian Limestone is 

 penetrated to a depth sometimes of 60 metres by large pockets, 

 filled by coarse sand, with grains of flint and small phosphatic 

 nodules of chalky consistency. The pockets also contain blocks of 

 Urgonian flint, with the casts of such characteristic fossils as 

 Requienia and Monopleuva ; but there is no trace of vertebrate bones. 

 In the second type, narrow and irregular cracks, sometimes 20 to 30 

 metres deep, furrow the Urgonian plateau in all directions. They 

 are filled by a calcareous clay of reddish colour, more or less fer- 

 ruginous, and richer in phosphate than the first kind of deposit. 



