Royal Physical Society. 55 



3. On Mesolite ; Faroelite (Mesole) ; and Antrimolite. By 

 M. Fokster Heddle, M.D. 



By a series of analyses of these minerals, Dr Heddle showed that Me- 

 and Mesole were not only distinct from Scolezite and Natrolite, 

 but also from each other ; the Antrimolite of Thomson he referred to 

 Mesolite, under which mineral also he considered that the Harringtonite 

 of Thomson would fall. 



The nomenclature of these zeolites seemed to be in a sad state of confu- 

 sion. We had Mesotype, Mesolite, Mesole. Dr Heddle proposed that 

 the unmeaning Mesotype be dropped for the expressive Natrolite ; that 

 Mesolite, as being in reality the intermediate mineral, be retained, and 

 that Mesole give place to Faroelite, from the locality whence we obtained 

 the choicest specimens of this substance. 



From their composition, these minerals rank as follows : — 



Natrolite, Na 0, Si 3 + Al 2 3 , Si 3 + 2 HO. 

 Faroelite, (Na 0, Ca O 2 ) Si 3 3 + 3 Al 2 3 , 2 Si 3 + 8 HO. 

 Mesolite, (NaO, Ca O 2 ) Si0 3 3 + 3 (Al 2 3 , Si0 3 ) + 8 HO. 

 3 , Si0 3 + 3 HO. 



4. Mr David Page exhibited specimens of the Woodocrinus Macro- 

 dactylus, a new genus of Encrinite recently figured and described by M. 

 de KonincJc. 



This rare and beautiful crinoid had as yet been found only in the 

 upper beds of the carboniferous limestone in Yorkshire, and had been 

 named by M. de Koninck after its discoverer, Edward Wood, Esq., 

 Richmond, one of the most zealous and indefatigable of English collectors. 

 The distinguishing features of the new encrinite were — its perfect sym- 

 metry of arrangements, the body and arms, when extended, presenting a 

 remarkable resemblance to the free-floating star-fishes. Its base consisted 

 of five pieces, which, branching into ten sub-basals, again subdivided 

 into twenty tapering fingers elegantly fringed with minute plumules. 

 The stem was also peculiar in its jointings, the pieces being of equal size 

 in the young stage, alternately large and small in the growing stage, 

 and in the mature form presenting a double alternation of larger with 

 smaller jointings. In few genera of the family were the parts so elegantly 

 and symmetrically disposed ; and from the peculiar construction of the 

 cap and fingers, there was little difficulty in distinguishing the Woodo- 

 crinite from other species. As yet it had been found only on the upper 

 verge of the limestone, and immediately under the millstone-grit of York- 

 shire ; but he (Mr Page) had little doubt that the Scottish mountain 

 limestone (which had yielded all the English forms) would also be found 

 to contain the Woodocrinus. At all events, the Petalodus, which ap- 

 peared to be a regular accompanying fossil in Yorkshire, had been found 

 both at Carluke, at Bathgate, and in Fifeshire. 



