150 PROCEEDINGS OF THE AMHERST MEETING 



are associated with coarse crystalline calcite, through which the crystals run 

 in metallic shiny prisms in every direction. The ore also impregnates the 

 limestone adjacent to the main vein. It seems to have been deposited by 

 ascending waters which had risen through the Ordovician (?) beds and spread 

 out below the overlying shales. No igneous rocks were found in the vicinity. 

 Mining is just started in the vein itself. Earlier work is in the float only. 



The furnace for reducing the ore is a small brick reverberatory hand-feed, 

 wood-burning affair. 



The paper summarizes briefly what is known of other Chinese antimony 

 mines and their geologic relations. 



Presented by title in the absence of the author. 



SOURCE OF THE SULPHATES IN THE SALINA BEDS 

 BY DAVID H. NEWLAND 



(Abstract) 



The calcium sulphate present in the Salina formation throughout much of 

 its areal extent is considered to be an integral part of the stratified series, 

 deposited under surface conditions along with the limestones, salt, and shales. 

 No substantial evidence of secondary origin of the sulphate through the de- 

 composition of limestone by sulphuric acid waters has yet been deduced or 

 seems likely to appear, in view of the extensive explorations that have already 

 taken place. Consequently, it seems hardly proper to consider the salt and 

 sulphate minerals as unconnected occurrences. It is likewise quite certain 

 that most of the calcium sulphate exists in the anhydrous form rather than 

 gypsum. The gypsum deposits are superficial, arising from the hydration of 

 anhydrite, which predominates below a depth of a few hundred feet. 



Evidence of the primary nature of the sulphate is: (1) The principal de- 

 posits have the shape of thin seams interstratified in nearly horizontal lime- 

 stones and showing no marked irregularities of contact above or below, except 

 as these arise from solution. (2) The more substantial beds spread over areas 

 of many acres or even several square miles and terminate by gradual wedging 

 out. Their position in the stratified series is constant. (3) The deposits are 

 remarkably free of foreign inclusions, though they may carry disseminated 

 impurities of calcarous or clayey nature. No residual bodies of shale or lime- 

 stone occur in the mined deposits. (4) The beds are found below the zone 

 reached by ground-water circulations, for they persist at depths where the 

 lock-salt still remains in force. (5) Metallic sulphides are not found in the 

 Salina in sufficient amount to account for the sulphate locked up in the two 

 minerals, and there is strong evidence to indicate that they were never present. 



The irregularities exhibited by gypsum, as described or depicted in early 

 reports, occur on the outcrop, where solution is at work, or more rarely may 

 be attributed to deposition by water of the sulphate derived from the lower 

 zone. To the latter agency is also to be ascribed the veins and cavity fillings 

 that accompany the beds. 



Presented l>v title in the absence of the author. 



