﻿REPORT OF THE DIEECTOR I9IO 149 



are heavy deposits of tough gypseous clays and fine clear cliffs 

 of crystallized gypsum. All through the volcanics are seams and 

 crystallizations of gypsum, permeating the mass through a multitude 

 of crevices so that large blocks of trap lie entirely surrounded by 

 gypsum. Wherever the trap extends the gypsum follows. In the 

 course of this trap dike westward across Grindstone island the sur- 

 face is broken up into kettle holes and knobs where the gypsum has 

 undergone secondary change, and where it comes out at the western 

 side of the island near Cape, le Trou the white gypsum cliffs stand 

 up brilliantly, with diabase on one side and fossiliferous magnesian 

 limestone on the other. Wherever the volcanics are well developed 

 the gypsum appears and seems always to occur in the presence 

 of the volcanics, except on Grosse Isle Head where a -mall area 

 of gypsum lies in the gray hard sandstones, and the -olcanics, 

 if present, are concealed under an overgrown surface. With- 

 out attempting to solve the problem of these interestii < occur- 

 rences it may be said that there is very little lime left in the exposed 

 rocks of the islands — too little by far to indicate an adequate sup- 

 ply for the lime in these masses of gypsum 1 and if the sulfur in 

 the combination has been supplied by the lavas (which seems, in 

 view of the intimate association of the masses, an almost unavoid- 

 able inference) it must have found its lime in some deeper s< rce of 

 older rocks. 



Gypsum. The open display of this mineral is brilliant. In the 

 sea faces of Grindstone and of Alright and the weathered pinnacles 

 near Cape le Trou, the rock varies in color through white, gray and 

 pink-white into saffron, red and black; most of it is mottled black 

 and white in laminated colors and all is compact and solid. In 

 secondary deposits among the cavities of the lava are sheets of satin 

 spar together with great crystallizations from a foot's length to the 

 size of one's arm. Some desultory efforts were made years ago to 

 find a market for this gypsum but the material was carelessly 

 selected and taken as ballast to Quebec; the attempt was not really 

 a serious one. The natural supplies lie at the water's edge, working 

 would be free and open and transportation by water to Montreal 

 would give a short haulage by rail to manufacturing centers; by 

 water to Pictou, Boston or New York would grade the haulage 

 according to the port. I have had a series of analyses of the gypsum 

 rock made by Dr E. W. Morley which give some clue as to the 

 ability of the material to meet present commercial demands. These 



1 A million tons of gypsum are easily available on the island of Grindstone 

 alone. 



