Apkil 3, 1908] 



SCIENCE 



537 



into a perfect sponge. " Equilibrium of 

 Animal Form," by Hans Przibram. " The 

 Effect of Degree of Injury, Successive Injury 

 and Functional Activity upon Regeneration 

 in the Scyphomedusan, Cassiopea Xamach- 

 ana," by Charles Zeleny. The present study 

 is a part of a series of experiments whose 

 object is the investigation of some of the 

 internal factors controlling regeneration in 

 several representative forms. It is found 

 that removal of six of the eight oral arms in 

 Cassiopea constitutes the most favorable de- 

 gree of injury for the regeneration of each 

 arm, and that from this optimum there is a 

 decrease in both directions. The data for 

 successive injury show a greater rate of regen- 

 eration of the margin of the disk after the 

 second removal than after the first. A com- 

 parison of the rate of regeneration of the 

 margin in cases where the disk was made to 

 pulsate rhythmically with cases without pulsa- 

 tion shows no advantage in favor of the pulsa- 

 ting ones, but rather a retardation. " Studies 

 in Adaptation — I., The Sense of Sight in 

 Spiders," by Alexander Petrunkevitch. This 

 article shows the relation between the position 

 of the eyes on the cephalothorax and the par- 

 ticular locomotion in hunting spiders, and by 

 the application of a new method makes pos- 

 sible the determination of the maximum 

 angles and of the limit of vision for each eye. 



SOCIETIES AND ACADEMIES 



THE GEOLOGICAL SOCIETY OF WASHINGTON 



At the 200th meeting of the society, held 

 in the Cosmos Club, on Wednesday evening, 

 February 12, the following papers were pre- 

 sented : 



Regular Program 

 The Barringer Hill (Texas) Pegmatite Dike: 



Frank L. Hess. 



This dike by its resistance to erosion has 

 formed a low hill in the flood plain of the 

 Colorado Eiver, and was named for the dis- 

 coverer. The minerals of the dike have un- 

 usually large dimensions, the quartz occurring 

 in masses 40 feet in diameter; the feldspar in 

 masses 30 feet across, with individual crystals 

 having edges 34 inches long; while fluorite 



crystals enclosed in quartz show edges a foot 

 long. A great variety of rare-earth metal 

 minerals occur in the dike, of which the yttria 

 bearing minerals, fergusonite and gadolinite 

 are mined commercially. Allanite occurs in 

 masses weighing over 300 pounds, fergusonite 

 up to 65 pounds and gadolinite up to 200 

 pounds. So far, no other important occur- 

 rences of the rare-earth metal minerals have 

 been found in the neighborhood. 

 The Structure of the Marhle Belt of Fannin 



County, Georgia: Laurence LaForge. 



The marble occurs in two lines of exposures, 

 occupying a double valley from one to three 

 and one half miles in width, cut about 250 

 feet below the general level of the region, and 

 with a low central ridge of mica slates. Owing 

 to strike faults, there is not a complete sec- 

 tion, nor do the formations occur in complete 

 normal sequence anywhere in the immediate 

 region, and attempts to unravel the structure 

 were unsuccessful until the key was furnished 

 by the sequence of the formations determined 

 by Mr. Keith in the ISTantahala Quadrangle in 

 North Carolina. 



The structure shows the valley to be in gen- 

 eral synclinal, but with a subordinate axial 

 anticline, the two lines of marble thus occupy- 

 ing the lateral synclinal axes, and the slate of 

 the central ridge belonging in a formation 

 underlying the marble. Both the central anti- 

 cline and the lateral synclines are broken by 

 thrust faults, so that the marble occurs in 

 discontinuous patches, and on the western side 

 of the valley one and sometimes two of the 

 underlying formations are faulted out. Noth- 

 ing is known of the actual dip of the faults, 

 but certain considerations lead to the conclu- 

 sion that they are steeply inclined, and that 

 the western fault is overthrust from the west, 

 the other two being overthrust from the east. 



Oxygen Values and Coal Alteration: Mr. 



David White. 



Elimination of oxygen is the preeminently 

 important feature from the standpoints both 

 of coal efficiency and coal development. This 

 deoxygenation, largely accomplished during 

 the first or biochemical (putrefaction) stage of 

 coal formation, continues during the second. 



