cxlv 



His other paper was on 

 "The Oaks of the United States." The very many different species of Oak 

 which abound in different parts of the United States, the largest number 

 being found in the Carolinas, have been, like the Cedars, so confused by 

 botanists, that he had given the matter much study for the purpose of 

 bringing order out of confusion. 



Both papers were referred to the Committee on Publication. 



Mr. Riley also presented two papers for publication, one "De- 

 scriptions and Natural History of two Insects which brave the 

 Dangers of Sarracenia variolaris" ; the other, " Notes on the 

 Yucca Borer, Megathymits yitccce." They were both referred 

 to the Committee on Publication. 



October 5, 1874. 

 W. T. Harris, President, in tne chair. 



Eighteen members present. 



A large amount of correspondence and a large number of ex- 

 changes were laid before the Academy by the Corresponding 

 Secretary, and on motion he was instructed to send a series of the 

 Transactions, excepting vol. i , to Mr. B. W. Irving of Tecumseh, 

 Nebr., in consideration of a donation of birds' eggs collected at 

 Tecumseh, Nebr. 



Dr. Stevens, who had just visited the Onondagua limestones of 

 New York, exhibited a number of fossils including two fine speci- 

 mens of trilobites, which he had collected there. 



Mr. Gage, from the committee appointed to investigate certain 

 mounds, reported having done so, and that he will lay the results, 

 with specimens, before the Academy at a future meeting. 



Dr. Geo. Engelmann then gave an interesting account of obser- 

 vations, geological and botanical, made during the summer in the 

 Rocky Mountain region of Colorado. 



He referred to the gradual and continued rise from St. Louis to the foot of 

 the mountains, scarcely noticeable as one travels over the plains except by 

 the uniform eastward flow of the rivers; to the fact that coal of good qua- 

 lity, belonging to a later formation than the carboniferous, and probably 

 to the cretaceous or tertiary, was found in the foot-hills of the mountains, 

 and to the prominence on the plains of the buffalo-grass. He dwelt on the 



