1881.] natural sciences of philadelphia. 11 



January 18. 

 The President, Dr. Ruschenberqer, in the chair. 

 Twenty persons present. 



January 25. 



The President, Dr. Ruschenberqer, in the chair. 

 Twenty-one persons present. 



Jos. J. Knox and Geo. H. Rex, M. D., were elected members. 

 Chas. Velain, of Paris, was elected a correspondent. 



February 1. 

 Mr. Geo. W. Tryon, Jr. in the chair. 

 Ten persons present. 



February 8. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-seven persons present. 



Note on Treeless Prairies. — Mr. Thomas Meehan remarked that 

 the absence of timber or arborescent growth on the grassy prairies 

 of America, still continued to be a matter of controversy, but he 

 believed that in the light of accumulating evidence, we mip-ht 

 now come to a positive decision in regard to the question. The 

 most prevalent belief had been that trees would not grow on 

 these prairies, — and we have had theories relating to soil or 

 climate, to show why they could not grow. Then there were 

 others who believed that trees did grow there in ancient times, 

 but had been burnt off, and kept burnt off by annual fires. 



Mr. Meehan considered in detail, the authors who had pro- 

 pounded various theories, and the distinguished men who had ad- 

 vocated them, and said that it was evident climate could have 

 nothing to do with the question, because in these prairie regions 

 there were often large belts of timber lands, projected like huge 

 arms into the grassy regions, with precisely the same climatal 

 conditions over both. That the soil was not unfavorable, was 

 proved now by the artificial plantations everywhere successful 

 and that the soil was unfavorable to the germination of tree seed 

 as suggested by Prof. Whitney, was on the face of it untenable 



