xlviii 



piece of copper, the use of which he did not know. He had seen 

 a stone pipe from the same mounds, of beautiful workmanship, 

 and bluish-gray in color, not red as usual. He remarked that 

 articles of copper had been found in Mexico which the form of 

 crystalization proved to have been brought originally from the 

 copper mines of Lake Superior. 



Dr. Wislizenus reported the mean temperature for May at 

 68.9°, the usual average being 66.3°. Highest, 95° ; lowest, 40.5°. 

 Rainfall, 3.01 inches, the usual average being 4.94 inches. 



Messrs. William Twining and J. B. Merwin were elected asso- 

 ciate members. 



July 3, 1871. 



The President in the chair. 



Foreign exchanges received through the Smithsonian Institu- 

 tion were laid upon the table, and a letter from the In&titution of 

 Archives, Florence, Italy, asking for an exchange of publications, 

 was appropriately referred. 



Dr. Engelmann presented a specimen of coal from Colorado 

 Territory. This coal had been found in several places on the 

 eastern base of the Rocky Mountains. He stated that it had 

 proved, upon examination, to be entirely destitute of bitumen, 

 and could not be used in the manufacture of gas, though it was 

 useful for fuel under locomotives and for other purposes. He 

 was of the opinion that it belonged to a much later period than 

 the other coals of the United States, probably the Cretaceous. It 

 had been found in large masses in many localities. 



In answer to inquiries by the President, Dr. Engelmann stated 

 that the large trees of Calaveras County, California, belonged to 

 the order of coniferous trees, of which the common cypress, juni- 

 per, &c., were species. They bore close relations to fossil speci- 

 mens found in the Tertiary formations, not only in this country, 

 but in Europe, confirming the already well-established fact of 

 the similarity of the vegetation of the Tertiary period on the two 

 continents. The age of these great trees had been overrated. 

 One of the largest felled had about 1,200 rings, so that the age 

 was 1,200 years. The impression had gone abroad that no 

 young trees of this species were ever found, but this was a mis- 



