252 Hill — Occurrence of the Texas Mercury Minerals, 



generally intimatel}' mixed with crystalline masses of calcite, 

 occurring in the interstices between them in the form of 

 globules. Some of these cavities have yielded over twenty 

 pounds of the native metal. This metal is also j^resent in 

 the clay lillings of seams and in one instance in a close-grained 

 cream-colored limestone. 



Calomel, which is present in small quantities, is found in 

 crystalline masses with practically the same association as the 

 native mercury. The calomel has generally a few crystals of 

 " terlinguaite " associated with it. 



The new minerals eglestonite and montroydite, described by 

 Prof. Moses from material sent to him by the writer, have 

 been found in only one locality, which was a viigg in a calcite 

 vein. The material was associated with considerable native 

 mercury and what is locally known as amalgam, a mixture of 

 cinnabar and native mercury. Here also was found the 

 crystallized terlinguaite described in the following paper. 



The deposits in the Uj)per Cretaceous are found in veins in 

 the Eagle Ford shales. The ore is not associated with calcite 

 to such an extent as is that of the Lower Cretaceous. The 

 veins are of the Ussure type and are filled with clay and 

 gypsum, with subordinate quantities of iron oxides and calcite. 

 A considerable quantity of iron pyrites occurs with the ore, in 

 this respect furnishing a contrast to the deposits of the Lower 

 Cretaceous. 



The only mercury minerals found in the Upper Cretaceous 

 are cinnabar and native mercur3^ 



