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XVI. Contributions to the Mineralogy of Nova Scotia. By 

 Henry How, D.C.L., Professor of Chemistry, University of 

 King* 8 College, Windsor, J\ova Scotia. 



[Continued from S. 4. vol. xli. p. 274.] 



VII. Some Triassic Trap Minerals. 

 (CENTRALLASSITE.— Hho publication of a letter on 

 ° " Doubtful Minerals " in the < Chemical News ' (vol. xxx. 

 p. 1G5), has recalled my attention to some mineralogical work 

 which occupied a good deal of my spare time in former years. 

 In that letter, and in others subsequently written to the same 

 Journal on the topic indicated, allusion is made to some of 

 this work ; and I open this communication with an attempt to 

 make matters clear so far as this is concerned. 



In 1859 I described (in the ' Edinburgh New Philosophical 

 Journal,' vol. x. p. 84) three minerals found in trap of Tri- 

 assic age near Black Rock in the Bay of Fundy, which I con- 

 sidered new, and which I called cyanolite, cerinite, and cen- 

 trallassite : they are among the " doubtful minerals " of the 

 letters above mentioned. I have nothing to add to what was 

 originally given with regard to the first two of these ; but I 

 find, on referring to my notes, that I can contribute something 

 more to the history of the third ; and while preparing this 

 paper, I have found occasion to reclaim a formula assigned to 

 a related mineral by its discoverer, the late Professor Anderson, 

 of Glasgow. Some notes respecting other trap minerals and 

 the rocks in which they occur are added. 



The three minerals mentioned were found constituting a 

 nodule : cyanolite had somewhat the characters of chalcedony ; 

 centrallassite was a colourless lamellar mineral in radiated 

 spherical concretions, and cerinite a yellowish waxy-looking 

 mineral enveloping the others. From the analytical details 

 obtained I thought I was justified in giving formula? for the 

 minerals ; and as regards the first two (cerinite contained 

 alumina), their relations, as made out, are shown by taking 

 the same number of equivalents of lime (the base in each for- 

 mula), in this manner (using the notation then in vogue) : — 



Gyrolite 2CaOSiO. + 3HO, } =4CaOSi 3 +6HO 

 taken twice .... J • . 



Okenite,3CaO,4Si0 3 + 6HO, |_ 4C Q „e [0 ■ 8H0 

 + 1 its formula . . . j - 4UlU ^3 &iU 3 + 8±LU 



Centrallassite ...... = 4CaO,5Si0 3 +5 HO 



Cyanolite = 4CaO, 10SiO 3 + 5HO 



I did not fail to state that centrallassite came near gyrolite 

 in physical characters and chemical composition. Dana's cri- 



