M. Ulex on SCruvite. 127 



Concerning the locality where the crystals are found, we 

 perceive below the upper strata, at a depth of 6 to 12 feet, a 

 large quantity of cattle-dung mixed with straw, in a state of 

 putrefaction. This passes by degrees into a black peat earth, 

 which extends to a depth of 26 feet and rests upon gravel. 

 The peat earth, of a thickness of 10 to 12 feet, consists of a 

 homogeneous impalpable mass, mixed here and there with 

 small parts of vegetable remains (parts of grasses; Sphagnum 

 and other mosses could not be detected). This is the true 

 matrix of the crystals, in which here and there blue iron earth 

 (protophosphate of iron or vivianite) is also found. 



By drying in the air it loses 40-50 per cent, of water, and 

 is not to be distinguished from the heavy black turf. 



Water dissolves very little from it. The solution is of a 

 light brown colour, without any reaction upon litmus. Heated, 

 it gives off at first some ammonia; in other respects it smells 

 and burns like turf, with a bright flame. The ashes which 

 remain vary in weight from 20-30 per cent. ; moistened with 

 water it does not act upon litmus. 



A quantity dried at 212° F. was subjected to analysis ; 100 

 parts of it gave — 

 2*0 per cent, soluble in aether (principally chlorophylle). 

 1*5 ... ... alcohol (principally resinous matter). 



1*5 ... ... water (principally salts of humous 



acids). 

 36*0 ... ... liquor potassae (principally humous 



acids). 

 36*0 ... organic residue (principally humine and vege- 

 table fibrine). 

 23*0 ... inorganic residue, consisting of — 

 0*3 ... soluble in water (sulphate of potass and chlo- 

 ride of sodium, no phosphates of alkali). 

 11*5 ... soluble in hydrochloric acid (principally alu- 

 mina and phosphate of magnesia and lime, 

 less peroxide of iron and sulphate of lime). 

 12*2 ... insoluble in hydrochloric acid (sand; calcined 

 with soda and decomposed by hydrochloric 

 acid, it gave 11 silica, 1*2 alumina, and per- 

 oxide of iron). 

 The analysis shows that we have a humous mass, which has 

 been formed from organic matters by putrefaction and decay. 

 It is probable that these matters were principally the excre- 

 ments of Herbivora ; a presumption which is supported by the 

 analysis of the ashes, from the quantities of phosphate of mag- 

 nesia and lime. 



The solid excrements of the Herbivora are characterized 



