ioo REVIEWS 



Gypsum Deposits of the Maritime Provinces. By William F. 

 Jennison. Canada Department of Mines, No. 84, 191 1. 

 Pp. 170, figs. 19, pis. 36. 



This report is largely taken up with general discussion of the world- 

 distribution of gypsum, its origin, manufacturing processes, and the 

 character of the manufactured products. Considerable space is given 

 to descriptions of various local occurrences that may become of com- 

 mercial importance. 



Nova Scotia, New Brunswick, and the Magdalen Islands make up 

 the Maritime Provinces. The gypsum deposits were thought at one 

 time to belong to Permian age, but they are now known to be Mississip- 

 pian. In Nova Scotia the deposits are not limited to any particular 

 horizon, but are found near the base, in the middle of the system, and 

 immediately underlying Pennsylvanian coal beds. They are in all cases 

 associated with marine limestones and marls, and the author believes 

 this fact is of great significance. The gypsum is found in beds ranging 

 up to 100 feet thick and in many places is seen to grade into the limestone. 

 The deposits in other provinces present no additional features of interest. 



The author believes the gypsum comes from conversion of submarine 

 limestones or marls by the action of free sulphuric acid of juvenile 

 origin. In support of this theory he points out that numerous circular 

 blowholes found in massive formations of the gypsum were vents for 

 escaping gases developed by the action of sulphuric acid on the calcareous 



materials. 



W. B. W. 



Colorado Ferberite and the Wolframite Series. By F. L. Hess and 

 W. T. Schaller. U.S. Geol. Survey, Bull. 583. Pp. 75, 

 pis. 14, figs. 35. 



In 1910 the Colorado field, chiefly in Boulder County, furnished 

 approximately one-sixth of the world's production of tungsten ore. In 

 no other field is the iron tungstate the principal ore mineral. 



In the first part of the report, Hess discusses the mode of occurrence 

 of ferberite in this district, the mineral associations being given in con- 

 siderable detail. He also submits 95 out of 300 analyses examined to 

 obtain a basis for differentiation from the remainder of the wolframite 

 group. He proposes the following definition of the group: At one end 

 of the series shall be placed ferberite, ranging from pure FeW0 4 to a 

 composition bearing 20 per cent of the hubnerite molecule MnW0 4 , and 



