158 Intelligence and Miscellaneous Articles. 



tained moreover peroxide of iron, lime and magnesia ; a portion of 

 the two latter still remained to be estimated in the ammoniacal filtered 

 liquor. The three above analyses, the third of which yielded the 

 best results, afforded the following proportions : — 



I. n. III. 



Silicic acid 2' 68 



Phosphoric acid 41*89 40-23 39-56 



Magnesia 4204 38-49 46-07 



Lime 165 4*40 2-32 



Protoxide of iron .. 2*72 3-31 4-47 



;ijw Alumina 0"55 0*96 



Ijitj; Fluorine 9*12 



liia/ 103-22 



The silicic acid is merely mixed with the wagnerite in the form of 

 quartz, it must therefore be deducted. The same holds good with 

 the alumina and small quantities of the remaining bases, which are 

 combined with carbonic acid, forming calcareous and bitter spar, and 

 cannot be completely removed in selecting the fragments. Their 

 amount is however very inconsiderable. If we deduct the 2' 68 per 

 cent, of silica there remain 40-61 per cent, phosphoric add, 46*27 

 magnesia, 4-59 protoxide of iron, 2-38 lime, 9-36 fluorine; results 

 which do not differ to any extent from those of Fuchs except in the 

 proportion of fluorine. If we calculate from the third analysis, we 

 find that the quantities of protoxide of iron and lime, which nearly 

 replace one part of magnesia, amount to one equivalent for 4-43 of 

 the latter. Now 9-36 fluorine to form MgFl require 6-34 Mg= 10-34 

 magnesia ; consequently 40-36 per cent, of magnesia remain to com- 

 bine with the 40" 61 per cent, phosphoric acid. But as the above ex- 

 periment could hardly yield the entire amount of phosphoric acid and 

 of fluorine, we have no hesitation in regarding the magnesian phos- 

 phate as 3MgO, PgCj, assigning to wagnerite the formula Mg Fl 

 + 3MgO,Po05. This formula requires 43-32 per cent, of phos- 

 phoric acid and 11-35 per cent, of fluorine, whilst the formula 

 MgFl + 4MgO,Pc,05 requires only 38-5 phosphoric acid, thus less 

 than the experiment yields, and 55-73 magnesia ; it is therefore in- 

 correct. 



In the specimens of the wagnerite selected for analysis, there were 

 reddish, dull, and soft portions, the examination of which showed 

 that they were probably decomposed wagnerite ; they consisted prin- 

 cipally of silicic acid. On analysis they yielded 93-81 per cent, silicic 

 acid, 1-87 phosphoric acid, 1-41 alumina and peroxide of iron, 2*58 

 , lime, and 1-49 magnesia. — Poggendorff's Ann. Ixiv. p. 251. 

 [To be continued,] 



ON THE STRUCTURE AND RELATIONS OF CORNULITES AND 



OTHER SILURIAN FOSSILS. BY MR. J. W. SALTER. 



The singular fossil named CorniiUtes serpularivs is well known as 



characteristic of the Silurian rocks of Gothland, Britain and North 



America, and its affinities have been the subject of much conjecture. 



