390 E. W. Berry — Age of the Dakota Flora. 



The Woodbine flora appears to me to be intimately as- 

 sociated with the Benton transgression. Moreover I have 

 long been of the opinion that the Washita fanna is of 

 Cenomanian age and therefore Upper Cretaceous, which 

 so far as I can learn, is the opinion of every competent 

 paleontologist who has studied the faunas. I might men- 

 tion Bose's work in Mexico or that of Whitney on the 

 fauna of the Buda limestone. It is also not without inter- 

 est in this connection that such of the Fredericksburg and 

 Washita echinoids, ammonites, and other forms that have 

 an outside range, or the most closely related forms, in 

 northern Africa or South America, occur respectively at 

 horizons which European paleontologists have deter- 

 mined as Albian and Cenomanian, or even Turonian in 

 some cases. 



Possibly if the United States were smaller our paleon- 

 tologists could see beyond its borders, and then perhaps 

 even the magic of diastrophism might lose its potency. 



Aet. XXVI. — An Occurrence of Naumannite in Idaho; by 

 Eael V. Shannon. 1 



A specimen in the National Museum collections has re- 

 cently been examined and found to consist almost entirely 

 of naumannite, the rare selenide of silver which has not 

 heretofore been reported from the United States although 

 known from several mines in Mexico. 



The specimen in question was collected by George H. 

 Eldridge in 1893 from the Silver Stopes of the De Lamar 

 Mine, at De Lamar in the Silver City district, Owyhee 

 county, Idaho. This mine was noted for large bodies of 

 rich ore which in part occurred as a white to gray or 

 bluish clay which filled fissures and which contained large 

 amounts of a silver mineral in grains, shot, or larger 

 masses. This silver mineral which was malleable and sec- 

 tile was commonly supposed to be argentite. The speci- 

 men which has been found to consist of naumannite was 

 collected as a typical nodule of the argentite occurring in 

 the clay and it is quite possible that the silver in a large 

 part of such ore was in the form of the selenide rather 

 than the sulphide. 



1 Published by permission of the Secretary of the Smithsonian Institution. 



