208 LARSEN AND WHERRY: LEVERRIERITE FROM COLORADO 



through the cross-bar, F, in the manner shown. The ends of the 

 cross-bar are semicircular, the arc of the semicircle being down- 

 ward and pressing against the bottom of the circular hole in the 

 outer shell. When the bolt is turned, its rounded end, turning 

 in the depression in the bottom of the bomb, forces the cover 

 against the rim on the outer shell, thus compressing the gold wire 

 in C, and effecting a tight closure. The ends of the cross-bar 

 are cut away as shown, to enable it to be inserted after the bomb 

 is in place. , 



The cover shown in the sketch is easily made, and it is con- 

 venient to have several for different purposes. Thus, one is 

 provided with an exit tube and valve to permit the escape of the 

 vapor, and another has both an exit tube and a pressure gage. 



The above autoclave has been used for many experiments 

 with aqueous solutions at temperatures up to 300° and has given 

 complete satisfaction. 



MINERALOGY. — Leverrierite from Colorado. ] Esper S. Lar- 

 sen, Geological Survey, and Edgar T. Wherry, National 

 Museum. 



Occurrence. During the summer of 1916, in the course of a 

 geologic study of the San Juan Mountains under the direction 

 of Whitman Cross, one of the authors (E. S. L.) collected speci- 

 mens of a platy, foliated mineral, called "clay-gouge" by the 

 prospectors, in the gold-silver mines of the old mining camp of 

 Beidell, Saguache County, Colorado. The material was in 

 considerable abundance in the dumps of the Buckhorn and 

 Esperanza mines and is reported to occur in irregular bodies 

 up to several feet across. A study in the office has shown it 

 to belong to the leverrierite group of minerals. It is associated 

 with gold and silver-bearing psilomelanite, pyrolusite, and 

 quartz. The pyrolusite is in well-formed prismatic crystals 

 with very perfect cleavages and is probably derived from man- 

 ganite. The quartz is not abundant and is partly in well- 

 formed crystals, up to an inch or more across, projecting into the 



1 Published with the permission of the Director of the United States Geological 

 Survey and the Secretary of the Smithsonian Institution. 



