66 JOURNAL OF THE 



worn, and they are bedded with water-worn pebbles, sharks" teeth, 

 and pieces of bone. Their composition is pecuh*^ar and renders the 

 supposition that they are coprolites in anything like their original! 

 condition untenable. The characteristic thing about all af them is 

 20 to 50 per cent, of silica, as rather course, sliarp-grained sand. 

 They are by no means of uniform composition. The two chief 

 Tariants are the insoluble matter (sand) and the phosphate of lime» 

 The phosphate of lime varies from 10 to 60 per cent. The fallowing: 

 complete analysis shows the composition of one of them taken at 

 random. It proves one of the poorest ones i 



Insoluble matter (sand) 43-66 



Carbonate of Lime 3A-S^ 



Magnesia o.86» 



Potash and' soda . Ov39' 



Oxide of iron and alumina 0.56- 



Phosphate of lime ^g-Q^" 



Sulphuric acid . trace. 



Cnlorine ..1_ Jrace.. 



L0a.02 



Another specimen contained 31.66 per cent, of insoluble matter^. 

 15.94 of carbonate, and 42.09 of phosphate of lime. 



Nodules representing the extremes in eomposition are found side 

 by side. While they are all characterized by the same general prop- 

 erties, and especially by tMs coarse sand, one can find in a cubic foot 

 of this tiongfomerate every grade of phosphate nodule. All are- 

 more or less impregnated with the carbonate of lime and some con- 

 tain as much as' 40 per cent, Tlie cmiclusion seems irresistible that 

 this is not the first estate of the nodules. They would appear to be- 

 the result of the breaking up, wearing, commingling and rebedding- 

 of phosphate beds of different localities. The bedded phosphates^ 

 tvhicli their composition shows these nodules represent,, never vary 

 so much in composition in the same bed. The various individuals 

 found here must have come together from distinet and possibly widely 

 separated beds. 



The cement between the nodule is made from broken and, for the 

 most part, finely-ground shells. It is mostly quite pure. At French 

 Bros.* quarries, the lime deposit on top of the nodules gives from 95 

 to 97 per cent, of carbonate of lime. The cement broken from be- 

 tween the nodules at Castle Hayne was found to contain : 



Sand and insoluble matter -„---^ 3.04 per cent. 



Carbonate of lime.. ... ...90.80 



Phosphate of lime .... . 1.46 '* 



