Phvsj)h(tte of Lime in (he Mineral Kingdom. 131 



dance to rondei* tliem of mucli agricultural value, our colleague, Mr 

 Austen, was induced to investigate the mode of occurrence of the 

 phosphate of lime in liis own neighbourhood, that of Guildford. He 

 found that the phosphate of lime nodules are abundant in the upper 

 greensand. They also occur in the gault, in two distinct beds, re- 

 markably persistent, in the district. 



Mr Austen regards the phosphoric acid of the nodules as of animal 

 origin. When the nodules are rubbed down they present a concen- 

 tric arrangement oi parts, resembling bodies formed, like agates, by 

 infiltration into cavities ; and our colleague points out that, where 

 the casts of bivalve shells and ammonites are filled with matter con- 

 taining phosphate of lime, these forms must have been first inclosed 

 in the sand, that then the proper shelly matter was removed, and 

 finally that the earthy phosphate occupied the place of the hollow. 

 He supposes that the phosphoric acid may liave formed part of the 

 coprolitic matter of the time, this matter in part preserved with its 

 original external form, while more frequently it w-as broken up and 

 the component portions diffused amid the sand and ooze. He also 

 draws attention to the conditions to which the beds containing these 

 substances have been exposed since their formation, having been 

 covered by thick deposits, and having descended to depths beneath 

 the level of the sea, where they were exposed to an elevated tem- 

 perature corresponding with the depth and the amount of bad heat- 

 conducting bodies above them, so that many chemical changes were 

 effected, and among them a more general diffusion of phosphoric acid 

 in the mass. 



Mr Nesbit has also communicated to us some remarks on the pre- 

 sence of phosphoric acid in the subordinate members of the creta- 

 ceous series. He states that he mentioned to Mr Paine, in Novem- 

 ber 1847, the existence of a large amount of phosphoric acid in a fer- 

 tile Farnham marl, and that he subsequently obtained 28 per cent. 

 of phosphoric acid from portions of this marl, the general mass con- 

 taining about 2 per cent. Nodules from the Maiflstone gault also 

 gave him 28 per cent, of phosphoric acid. Other localities are no- 

 ticed, and as much as 69 per cent, of phosphoric acid is mentioned 

 as contained in a dark red sandstone rock occurring in masses in the 

 upper portion of the lower greensand at Hind Hill. 



Mr Wiggins has sent us a notice of the fossil bones and corproli- 

 tic substances discovered in the crag of Suffolk, remarking on the 

 value of the latter for agricultural purposes, — 200 tons of them having 

 been obtained from about a rood of ground ; an additional instance 

 of the remains of animals and their fa'ces, entombed in rocks of dif- 

 ferent geological ages, becoming available for the growth of existing 

 plants. 



As regards phosphate of lime and its dissemination, which modern 

 researches have shewn is much greater, when sufficient quantities of 

 rocks are examined, than appear from the analyses of the small por- 



