9 



phosphoric acid is mostly due to animal life ; and when we say " due "' 

 to animal life we wish to imply that animal life is the assimilating and con- 

 centrative medium of j^re-existing phosphoric acid : whether as sea and 

 fresh-water shells, as fish and animal bones, as excreta of birds and 

 saurians, etc., animal organisms have been from the beginning of life 

 and still are, the silent but mighty laboratory of nature, never resting to 

 collect and store up the dispersed molecules of phosphoric acid. 

 Among such are the guano beds of recent epochs, coprolite deposits, 

 bone beds, shell beds, etc. 



Nature's operations of bringing these materials or their debris 

 together to form whole geological areas are equally varied, but the 

 estuaries and depressions of the sea-bottcms of the different and respec-. 

 tive geological periods, are recognized to have been the receptacles or 

 storehouses of these wonderful supplies. A curious disposition to 

 concretionary action, displayed by nuclei of certain organisms to absorb 

 and accumulate phosphatic matter, with which the ancient seas 

 abounded, is more easily seen in its efifects than explained. 



Such is the origin of many odd species of nodules, some varieties 

 of which exist in immense quantities. 



The abrupt or imperceptible, but never ceasing operations of geo- 

 logical rearrangement, follow the afore mentioned accumulations, and j 

 we then have new forms of mineralized phosphatic matter, giving rise 

 to conglomerates, breccias, phosphatic limestone, shells and marls, 

 sandy and ablation deposits, etc., and most of the known natural de- 

 posits of mineralized phosphate display examples of two or more of 

 these products. For instance, the perplexities experienced just now 

 with some of the exploratory w^orkings of the lately discovered Florida 

 deposits, are chiefly occasioned by the character»of these beds contain- 

 ing boulders, and nodules from pea size to masses of several hundred 

 pounds in weight, fish bones, sharks' teeth and fossil bones, in fact debris 

 from several geological epochs, each of these materials naturally varying 

 in purity, and therefore also in commercial value, so that the more 

 successful enterprises may be looked for where regular and homogenous 

 deposits occur, or some cheap and efficient mechanical means are 

 applied for the separation of the marketable products from the less 

 valuable or worthless intermixtures. 



