13 



than thi'eo, and probably four species of wliales, then for the 

 first time added to the list of Biitish Fossil Mammalia.* 



My purpose, howevci", is more with the uses to which these 

 phosphatic nodules have been put, along with others obtained 

 from an entirely different bed in the Geological series, the 

 Upper Green-sand, to which I would no\;^ turn your attention, 

 and Avhich were also firft brought into notice by Professor 

 Henslow. 



He shall here again speak for himself In a communication 

 to the Gardener's Chronicle, in 18-48, he writes as folloAvs : — 



"It occurred to me that possibly certain nodules of an 

 " anomalous character, abounding in the Upper Green-sand in 

 " the neighbourhood of Cambridge, were in some respects allied 

 " to those in the Crag, and would j)ossibly be found to contain 

 " phosphate of lime. Upon directing the attention of Mr. Deck, 

 "■ of Cambridge, who is a practical chemist, engaged in making 

 " analyses for agricultural purposes, to these nodules, he readily 

 " detected in them the presence of earthy phosphates, in pro- 

 " portions varying from 57 to 61 per cent. Whether these 

 " various nodules, thus abounding in phosphate of lime, can be 

 " made available for agricultural purposes, must depend upon the 

 " possibility of their being collected at a cheaper rate than an 

 " equal quantity of bones can be." 



He little thought, when he wrote this, to what extent, within 

 a few j^ears after, these nodules would come to be used in 

 agriculture, and the value that would be set upon them. The 

 stratum of Green-sand in Avhicli they are found, "although never 

 more than a foot thick, occurs near the surface over many square 

 miles in the vicinity of Cambridge,' and the land is now in 

 places, as before observed, scored with the deep trenches dug to 

 get at them, finding employment for large numl)ers of labourers, 



* They are described and figured in Professor Owen's "History of 

 British Fossil Mammals and Birds,' p. 526. 



