LII BIOLOGICAL SOCIETY OF WASHINGTON. 



Forsterian period (1766-1785), named for George Reinbold Forster, 

 who was the first to publish a catalogue of the birds of North 

 America, and who also first published a special paper on a collec 

 tion of American birds sent to Europe ; (6) the Pennantian period 

 (1785-1791), marked by the labors of Pennant and Latham; (7) 

 the Bartramian period (1791-1799), named for John Bartram, the 

 first resident of America to publish a work on its birds; (8) the 

 Vieillotian period (1800-1808); (9) the Wilsonian period (1808- 

 1824), named after the first great American ornithologist; (10) the 

 Bonapartian period (1824-31), during which the impress of science 

 was laid upon the woodland genius of Wilson; (n) the Richard - 

 sonio-Swansonian period (1831-2); (12) the Nuttallian period 

 (1832-4), marked by the appearance of the first of American orni 

 thologists; (13) the Audubonian period (18341853), named after 

 the most brilliant of ornithologists, marked by the publication of 

 what Cuvier called the "grandest monument ever erected by art to 

 nature;" (14) the Cassinian .period (1853-58), named for John 

 Cassin, the best general ornithologist America has known ; (15) 

 the Bairdian period. 



The establishment of the American Ornithologists' Union, he 

 thought, would probably mark the beginning of a new epoch one 

 in which the existing intricacies of ornithological nomenclature 

 will, it is hoped, be straightened out. The present is simply a 

 period of transition. 



Dr. Coues laid before the Society the plate proofs of the forth 

 coming new edition of his Key to North American Birds. 



Mr. Walcott having received, since the last meeting of the So 

 ciety, on February 8, a number of additional specimens of the 

 granitic-like rock containing fossil Stromatopora, corals, plates of 

 crinoid stems, etc., from Litchfield, Maine, exhibited them and 

 said that he was incorrect in calling the rock a granite as it was of 

 sedimentary origin, a plastic rock so changed in the specimens ex 

 amined that it might be called a conglomerate gneiss. 



Mr. J. S. Diller stated that he had examined thin sections of the 

 rock under the microscope, which showed it to be chiefly crystalline, 

 and composed almost entirely of quartz and feldspar. These 

 minerals occur as irregular angular grains, which, for the most part, 

 have crystallized in their present position in such a manner as to 

 fill up the whole space. There is but little trace, as far as can be 



