proceedings: botanical society 83 



toward the east and north and is not visible on the north side of North 

 Mountain, where it is probably present, although thin and covered with 

 wash. Its greater thickness at Schaefferstown and south of Harrisburg 

 is probably due to the fact that at these localities it is overthrust from 

 farther south, where its thickness is greater. 



Certain rocks at the Cornwall mines south of Lebanon, Pennsylvania, 

 which were regarded as Hudson River shales by the Pennsylvania Geo- 

 logical Survey, were foimd to be metamorphosed siliceous banded lime- 

 stones of the Conococheague limestone of Upper Cambrian age. 



T. Wayland Vaughan: Significance of reef coral fauna at Carrizo 

 Creek, Imperial County, California. Owing to the lateness of the hour 

 this paper was postponed to another meeting. 



At the 312th meeting, held December 20, 1916, the presidential ad- 

 dress was delivered by the retiring President, Arthur C. Spencer: 

 Stream terraces in the Rocky Mountain province (Illustrated). The ad- 

 dress will be published at a later date. 



At the twenty-fourth annual meeting held on the same evening the 

 following officers were elected for the ensuing year: President, Walter 

 C. Mendenhall; Vice-Presidents, Frank H. Knowlton and Arthur 

 L. Day; Secretaries, H. E. Merwin and Esper S. Larsen, Jr.; Treas- 

 urer, B. L. Johnson; M ember s-at-large-of-the-Council, B. S. Butler, H. 

 S. Gale, C. W. Gilmore, R. W. Pack, and L. W. Stephenson. 



Carroll H. Wegemann, Secretary. 



THE BOTANICAL SOCIETY OF WASHINGTON 



The 116th regular meeting of The Botanical Society of Washington 

 was held in the assembly hall of the Cosmos Club at 8.00 p.m., Tuesday, 

 December 5, 1916, President T. H. Kearney presiding. 



The program of the evening consisted of a symposium on the behavior 

 of hybrids in different groups of plants. 



Mr. G. N. Collins discussed the behavior of Indian corn. In about 

 25 cases out of 50 where the vigor of first-generation hybrids had been 

 compared with that of the parents, definite evidence of greater vigor 

 was secured, and in no instance was there clear evidence of decreased 

 vigor. It was suggested that the differences in the degree of vigor 

 observed in different varietal combinations appeared to be influenced 

 by the length of time the parental strains have been isolated. Strains 

 which are widely separated geographically, and on this accomit proba- 

 bly have been kept distinct for long periods of time, usually exhibit the 

 greatest increase in vigor when crossed, while strains from the same or 

 adjacent regions, although they may show more marked morphologi- 

 cal differences, generally show a less marked increase in vigor in the 

 first generation of the cross. 



In a cross between two varieties having many sharply contrasting 

 characters, a comparison of the variability of the first and second gen- 



