188 



SCIENCE. 



[N. S. Vol. XI. No. 266. 



of the Ouachita Mountain Range in Indian 

 Territory.' 



This mountain range is 200 ihiles long and 

 trends west from the vicinity of Little Rock, 

 Arkansas, into Indian Territory. It is sepa- 

 rated from the Ozark uplift on the north by the 

 east and west trough of the Arkansas valley. 

 It is abruptly terminated on the east by the 

 Tertiary overlap of the Mississippi embayment. 

 The Cretaceous peneplain comes up on the south 

 side of the range and Cretaceous rocks conceal 

 much of the structure. On the west the strike 

 of the folds turns toward the south, and the 

 latter pass under Cretaceous sediments. As 

 far as known, the rocks involved in the Oua- 

 chita uplift are Silurian shales, sandstone, lime- 

 stone, and novaculites^2560 feet ; Lower 

 Carboniferous (Branner) — 18,480 feet; and 

 Upper Coal Measures — 5300 feet ; making a 

 column nearly five miles in thickness. The 

 sandstones become thicker and coarser toward 

 the south. 



The structure of the range is Appalachian. 

 In the center of the range the folds, in massive 

 sandstone, are wide and long. Near the pe- 

 riphery the folds are shorter and generally over- 

 turned, compressed and faulted. Some of the 

 faults have vertical displacements of several 

 thousand feet. The uplift began before or dur- 

 ing the Carboniferous and culminated after that 

 period. 



(2) Mr. Geo. P. Merrill : ' The Gem Mines 

 near Bakersville, North Carolina.' Specimens 

 were shown and a brief account given of the 

 pegmatitic veins in which the beryls (emeralds 

 and aquamarines) occur. 



(3) Mr. Arthur C. Spencer : ' A Peculiar 

 Form of Talus.' 



In some of the high basins of the San Juan 

 Mountains, Colorado, the encircling cliffs have 

 supplied at certain points an excess of debris, 

 which has advanced across the floor of the 

 glacial cirque as a tongue, simulating the form 

 of a small glacier. The slope of these lobes 

 may be as low as one in six, and their thickness 

 may reach fifty feet. The surface of the talus- 

 stream shows, in each case, a series of roughly 

 concentric ridges, suggestive of difierential and 

 periodic downward movement. The chief force 

 involved has doubtless been gravity, acting 



upon the mass of loose rock. The movement 

 within the mass may, however, have been facili- 

 tated by interstitial ice derived from sifting 

 snow or percolating water. 



F. L. Ransome, 

 David White, 



Secretaries. 



BIOLOGICAL SOCIETY OF WASHINGTON. 

 316TH MEETING, SATURDAY, JANUARY, 13TH. 



W. R. Maxon exhibited an abnormal flight 

 feather from the peacock, in which the shaft 

 was double for nearly its entire length. 



William Palmer exhibited a series of speci- 

 mens of Onoclea sensibilis showing variations 

 due to conditions of environment, such as shade, 

 exposure to light, moisture or dryness. 



Vernon Bailey told ' Where the Grebe Skins 

 come from,' and how the birds are killed by 

 thousands among their nests on the lakes of 

 eastern Oregon and California. Three species, 

 the western, the eared, and the pied- billed 

 grebe were found breeding among, the tules in 

 the shallow waters of Tule Lake, California, 

 and here the hunters were engaged in shooting 

 the old birds, stripping the skins from their 

 breasts and shipping them to San Francisco. 

 From twenty to fifty cents were received for a 

 skin and the hunters were making from twenty 

 to thirty dollars a day. At the present rate of 

 destruction the birds will not last many years 

 and the speaker raised the question, can they 

 not be protected ? 



William Palmer spoke of ' the Ferns of the 

 Lower Shenandoah Valley,' illustrating his re- 

 marks by specimens, showing their variation as 

 compared with similar species from the vicinity 

 of Washington due to the conditions under 

 which they grew. In the case of every species 

 but one the valley habitat was the dryer of the 

 two resulting in the production of narrower 

 fronds and less herbaceous plants. The de- 

 forestation of the valley and the grazing of 

 sheep and cattle have caused the almost com- 

 plete extermination of ferns, except in favored 

 and very rocky localities, among the limestone 

 bluffs and mountain streams. Many species 

 common about Washington, and growing luxu- 

 riantly in wooded situations, were either absent 



