410 REPOKT OF NATIONAL MUSEUM, 1899. 



The mineral is usually met with in very irregular masses, associated 

 with red marls, sandstones, and limestones, and varies much in charac- 

 ter. At Hillsborough, in the quarries being worked, ten to fifteen 

 years ago there was exposed a total head of rock from 90 to 100 feet, 

 of which about 70, forming the upper portion, consists mostly of 

 "soft plaster" or true gypsum, which rests on beds of hard plaster or 

 anhydrite of unknown depth. At the same point considerable masses 

 of very beautiful snow-white gypsum or alabaster are also met with, 

 associated with the varieties named above, but comparatively little 

 selenite, while at Petitcodiac, where the deposits has a breadth of about 

 40 rods and a total length of about 1 mile, the whole is fibrous and 

 highly crystalline and traversed by a vein of nearly pure selenite, 8 

 feet wide, through its entire extent. The rock on the Tobique River, 

 which rises in bluffs along the stream some 30 miles above its mouth, 

 is mostly soft, granular or fibrous, and of a more decidedly reddish 

 color than in the other localities. 



Important beds of gypsum belonging to the same geological horizon 

 likewise occur in Nova Scotia, particularly at Wentworth and Montague 

 in Hants County, at Oxford, River Philip, Plaster Cove, Wallace Har- 

 bor, and Bras d'Or Lake, Cape Breton. At Wentworth there are 

 stated to be "cliffs of solid snowy gypsum from 100 to 200 feet in 

 height." (Specimen No. 13690, U.S.N.M., from Windsor, Hants 

 County.) 



Gypsum deposits occur in the Onondago formations of Ontario, 

 Canada, and are exploited along the Grand River between Cayuga and 

 Paris. The mineral here occurs in lenticular masses varying from a 

 few yards to a quarter of a mile in horizontal diameter and from 3 to 

 7 feet in thickness. (See Specimen No. 62145, U.S.N.M.). 



The foreign sources of gypsum are almost too numerous to mention. 

 Important beds occur in Lincolnshire and Derbyshire, England; near 

 Paris, France, in Spain, Italy, Germany, Austria, and Switzerland. 

 The Paris beds are of Tertiary age, and the mineral carries some 10 to 

 20 per cent of carbonate of lime, together with silica in a soluble form. 

 The presence of these constituents is stated to cause the plaster to set 

 much harder, permitting it, therefore, to be used for external work. 

 The Italian gypsum is often of great purity. The finest alabaster is 

 stated to come from the Val di Marmolago, near Castellina. (Specimen 

 No. 63394, U.S.N.M.) 



Uses. These have been already, in part, noted. The principal uses 

 of gypsum of the ordinary massive varieties is for fertilizers (land 

 plaster) (Specimen No. 63059 U.S.N.M.), and in the manufacture of 

 plaster of pans, or stucco. (Specimens Nos. 53348, 53462, U.S.N.M.) 



As above noted, gypsum is but little used for building purposes, 

 being too soft. Several residences, a railway station, and other minor 



