278 Prof. How on the Mineralogy of Nova Scotia. 



mode of occurrence with the borate and chloride of magnesium, 

 called boracite, found at Stassfurt. When they occur with the 

 salts of sodium before specified, they exhibit the position of an 

 insoluble borate associated with soluble salts occupied by bora- 

 cite in carnallite and other chlorides at Stassfurt. The distri- 

 bution of the nodules of Ulexite in gypsum in this vicinity is 

 described exactly in the words used* with reference to the mag- 

 nesian borate, viz., " the nodules of boracite have the appearance 

 of having been shot at random from a park of artillery; so irre- 

 gularly are they scattered and so firmly are they imbedded." 

 Further, the latter is also found in beds of anhydrite and gyp- 

 sum ; and though Ulexite has not been met with here in anhy- 

 drite, I have seen it in a very thin vein of gypsum in that rock. 

 It is important to remember in this connexion that boracite is 

 anhydrous, while Ulexite is largely hydrated. 



Silicoborocalcite in Crystalline Nodules. — Recent observations 

 have also added to the mineralogical history of this species, 

 Howlite of Dana f. A pupil of mine, Mr. Keating, brought me 

 last May a nodule made up of pearly scales, which proved to be 

 the mineral in question. I subsequently obtained several spe- 

 cimens myself, and have quite recently had others, some being 

 larger than any previously seen by me, and the largest weighing 

 about two ounces, sent me from the same place. I had already 

 on one occasion noticed, as mentioned in my original descrip- 

 tion of the species J, a single nodule of similar characters from a 

 locality in Newport, the usual forms (found elsewhere) having 

 been at the same time described as dull and amorphous. Those 

 lately met with were from Winkworth, about two miles from 

 Windsor ; they were imbedded in gypsum, which also contained 

 Ulexite, most frequently alone, but sometimes underlying How- 

 lite; the nodules were of irregular form, well rounded, and, 

 when removed, left a smooth cavity in the rock; they were 

 seamed with gypsum and selenite in some instances, like the 

 amorphous nodules originally found : none of these were met 

 with in the Winkworth gypsum. The pearly scales were per- 

 fectly transparent under the microscope, and consisted apparently 

 of plates breaking with oblique cleavage-planes. In one form 

 or other Howlite has now been met with, always in gypsum or 

 anhydrite, at four localities lying from two to thirty miles apart, 

 and reported from two others, all in Hants county. 



Incrustation of Gypsum by Glauber salt and Epsomite contain- 

 ing Boracic Acid. — Clifton Quarry, Windsor, mentioned by me 



* "The Salt Deposits at Stassfurt," Chemical News, vol. xix. p. 78. 

 t Mineralogy. Fifth edition, p. 598. 

 \ Phil. Mag. January 1868. 



