396 THE GEOLOGIST, 



AMMONITES. 



Section I. — Back with entire keel. 



1. Arietes (ram-liom). 



2. Falciferi (sickle -bearing). 



3. Cristati (crested). 



Section 11. — Back crenated. 



4. Amalthei. 



5. Bhotomagenses. 



Section III. — Back sharp. 



6. Disci (quoit-sliape). 



Section TV. — Back ckannelled. 



7. Dentati (tootlied). 



Section V. — Back squared. 



8. Armati (armed). 



9. Ca/pricorni (gort-iiom). 



10. Ornati (ornamented). 



Section VI. — Back roimdj = convex. 



11. Heterophylli (odd-leaf). 



12. Ligati (constricted). 



13. Annulati (ringed). 



14. Coronati (coronate). 



15. Fimhriati (bordered). 



16. Cassiani [complex lobes]. 



(To he continued.) 



RESEARCHES ON P S E U D 0 M 0 R P H S, 

 By M. Delesse. 



Translated from tlie " Annales des Mines"* by H. C. Salmon, F.G.S. 



Metamokphism, considered in its widest generality, comprises all tlie 

 modifications wMcli mineral substances undergo. It is naturally 

 divisible into parts, according as its objects bear upon minerals or 

 upon rocks. It is tbe metamoi^bism of minerals wMcb I propose 

 studying in this notice, and I shall describe it under tlie name of 

 pseudomorpbism. But as certain associations of minerals present all 

 the appearances of pseudomorphism, with which they have been 

 often confounded, it is necessary, in the fii^st place, to consider these 

 specially. 



We know that, notwithstanding their great variety, the rocks 

 * Vol. xvi., p. 317 : 6th Hvi-aison. . 1859. 



