52 PROGRAMS AND ANNOUNCEMENTS 



age from Cambrian to Eocene, the Mesozoic section alone being approxi- 

 mately 14,000 feet thick 25 miles east. The sandstones of the Lower 

 Cretaceous are oil-bearing near Cody, and the oils are hght, relatively 

 clear, and have a paraffin base. Evidence in nearby regions shows that 

 the sedimentary rocks are much folded and that the lavas are cut by 

 many intricate fractures, some of which, at least, are of recent origin. 

 Sandstones outcrop on Shoshone River, 2| miles south of the oil spring 

 and about 400 feet lower, so that the lavas at the sulphur deposit are 

 probably not over 500 feet thick. 



The oil is probably to be traced to the sedimentary rocks, but its 

 close relation to the sulfur deposits is unusual. 



REGULAR PROGRAM 



The Joplin lead and zinc deposits: C. E. Siebenthal. • 

 Secondary enrichment in silver: E. S. Bastin. Microscopic studies of 

 specimens of silver ore collected by E. S. Bastin and J. M. Hill from 

 the mines near Lawson, Clear Creek County, Colorado, and near Cari- 

 bou, in Boulder County, show that the ores owe their value largely to 

 downward sulfide enrichment. The rich secondary sulfides are devel- 

 oped not only in cracks in the original ore, but as metasomatic replace- 

 ments of galena and quartz. Sketches were exhibited illustrating such 

 replacement. In the belief that such phenomena were of rather wide- 

 spread occurrence, a specimen collected by W. H. Weed from the Big 

 Seven mine, Neihart district, Montana, was polished and examined 

 under the microscope. Replacements similar to those in the Colorado 

 ores were well shown by the Montana specimen. 



Certain mineralogical differences between the ores which exhibited 

 enrichment in silver and other ores in the district which did not exhibit 

 such replacement were pointed out. R. W. Richards, Secretary. 



PROGRAMS AND ANNOUNCEMENTS 

 THE WASHINGTON ACADEMY OF SCIENCES 



January 30 at 8.15 p.m.. Cosmos Club Assembly Hall. Illustrated 

 lecture by Dr. Arthur L. Day, Some observations on the volcano Kilauea 

 in action. 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 86th regular meeting of the Botanical Society of Washington will 

 be held in the Assembly Hall of the Cosmos Club at 8 p.m., Tuesday, 

 February 4, 1913. 



SCIENTIFIC PROGRAM 



Brief Notes and Reviews of Literature. 



T. H. Kearney, Indicator value of natural vegetation in the Tooele 

 Valley. 



H. B. Shaw, The control of seed production in beets. 



The program will be followed by a social hour, with refreshments. 



