38 



Prof. How on the Mineralogy of Nova Scotia. 



trated by, NaCl, NaSO 4 , and CaSO 4 , &c. [sic]. Besides, water 

 has a decomposing action on the mineral." As regards purity, 

 I formerly found only a trace of chlorine in addition to the MgO 

 and SO 3 above named, and if any essential constituent had been 

 washed out it should have been the soda ; but my results cer- 

 tainly show no great deficiency of this. Respecting the whole 

 constituents, on comparing the statement above given of the 

 theoretical and actual percentages, I see no reason to abandon 

 my formula for natroborocalcite for that newly proposed. 



Probably this mineral will be found elsewhere in this district 

 and in other parts of the province where plaster abounds ; 

 indeed, from the description of a quarryman, I have little doubt 

 of its having been seen in another locality, unless the mineral 

 described to me as " a stuff softer than plaster, about the size of 

 eggs, coming clear out of the plaster and smelling like sulphur 

 or the stones of a grist-mill," should prove to be Hayesine, a 

 hydrated borate of lime sometimes confounded with natroboro- 

 calcite, which has not yet been found here, and which is de- 

 scribed by Dana as having a peculiar odour : I have not perceived 

 any odour in natroborocalcite. The other borates may of course 

 be also expected in new localities ; I have failed to find them in 

 plaster brought to Windsor from several quarries. 



Borates and other minerals, as characterizing the gypsum and 

 anhydrite. — Of course, in addition to the interest attaching to a 

 new member of the small class of mineral borates, and to the 

 only known qualitative analogue of datholite, silicoborocalcite 

 has that belonging to the first form in which combined silica has 

 been found in the enormous deposits of sulphate of calcium here. 

 It thus furnishes an addition to our means of learning the history 

 of these rocks which are being shown to exhibit interesting ana- 

 logies with similar formations elsewhere. I have thrown into a 

 condensed tabular form the chief facts at present known with 

 regard to the mineral contents of the plaster rocks in question, 

 thus : — 



r 



Hants County, 

 Nova Scotia, 

 has deposits 

 made up of 



Gypsum, 

 containing 



and 



Anhydrite, 

 containing 



"Natroborocalcite, cryptomorphite, silicobo- 

 rocalcite, glauber-salt, common salt, Arra- 

 gonite, calcite, and selenite as distinct 

 accessory minerals, and also, to be found 

 on analysis, carbonates, partly of mag- 

 nesia, and protoxide of iron, clay, and a 

 very small quantity of silica. 

 Silicoborocalcite, selenite, and Arragonite, 

 or calcite as accessory minerals, and also, 

 to be found on analysis, carbonates, 

 partly of magnesia, and a very little 

 silica. 



The detection of glauber-salt with the borates, and of chloride 



