1 882. 105 Trans. N. Y. Ac. Sci 



locality has been more than repaid by the sales of the gems (Hiddenites) 

 discovered. But for the liberal financial aid given to the writer by both 

 Mr. Richard H. Roberts, of Albany, and Mr. James D. Yerring- 

 TON, of Cresskill, N. J,, the work of discovery and development at this 

 locality would have been very much retarded, if not indefinitely post- 

 poned. 



DISCUSSION. • 



Dr. Newberry remarked on the extreme beauty of the specimens 

 exhibited by Mr. Hidden, and the great interest of these discoveries, 

 in which he had achieved such signal success, both practical and 

 scientific. 



Dr. R. p. Stevens made some further remarks on the communica- 

 tion, comparing the aspect of the specimens, and the mode of their 

 occurrence, with those of the emeralds from the celebrated locality 

 near Bogota. He referred to the fact, also, that the Bogota mines had 

 been worked by the early aborigines, and were doubtless the source of 

 the emeralds described with so much enthusiasm by the Spanish histori- 

 ans of the conquest of Peru. 



Mr. GEORGe F. Kunz exhibited a remarkable series of prehistoric 

 knives, flakes, and cores, of Obsidian, from the vicinity of the city of 

 Guatemala, Central America. They were obtained by the partial cut- 

 ting away of a mound, during the making of a new road, about six 

 miles from the city. The excavation revealed a sort of little cyst or 

 chamber, walled and roofed with slabs of stone or baked clay, within 

 which this large quantity of obsidian knives had been carefully and 

 quite regularly laid away. There was scarcely anything else in the 

 chamber, but the broken and worn edges of many of the implements 

 would indicate that they had been much used; and the suggestion is strong 

 that this may have been a sacrificial mound, and that these were the 

 implements used in the rites of sacrifice, perhaps for a long period. 



