822 



SCIENCE. 



[N. S. Vol. XV. Mo. 386. 



The Council also authorized the organiza- 

 tion of a Pacific Section of the Society, to 

 hold meetings in the vicinity of San Fran- 

 cisco. The first meeting of the new Section 

 has ' already been held, on Saturday, May 3, 

 a program of sixteen papers having been 

 provided for this occasion. 



The following papers were read at the 

 April meeting: 



Dr. H. F. Stecker : ' The curve of least contour 

 in the uon-euclidean plane.' 



Mr. J. L. CooLiDQE : ' Quadric surfaces in hyper- 

 bolic space.' 



Dr. F. H. Satfokd : ' Dupin's cyclides of the 

 third degree.' 



Mr. Petek Field : ' On the forms of plane uni- 

 cursal quintic curves.' 



Miss R. G. Wood : ' Non-euclidean displacements 

 and symmetry transformations.' 



•Mr. D. R. CuRTiss: 'A note on the sufficient 

 conditions for an analytic function.' 



Miss I. M. Schottenfels : ' On the definitional 

 functional properties for the analytical functions 

 (sin TTz)l'!T, (cos Ta)/7r, (tan ■Kz)lTt.' 



Professor C. A. Scott : ' On the circuits of plane 

 curves.' 



Dr. E. V. Huntington: 'A complete set of pos- 

 tulates for the theory of real numbers.' 



Dr. L. P. Eisenhabt : ' Surfaces whose lines of 

 curvature in one system are represented on the 

 sphere by great circles.' 



Professor E. H. MooRE: 'A definition of ab- 

 stract groups.' 



Dr. E. V. Huntington: 'A definition of ab- 

 stract groups.' 



Mr. L. D. Ames : ' Evaluation of slowly con- 

 vergent series.' 



Dr. Edward Kasneb: 'Groups of Cremona 

 transformations and systems of forms.' 



Mr. A. D. Risteen : ' The constant of space.' 



Dr. C. J. Keyser: 'Concerning the angles and 

 the angular determination of planes in 4-space.' 



Professor T. J. Pa. Beomwick: 'The infinitesi- 

 mal generators of parameter groups,' and ' On the 

 parabolas or paraboloids through the points com- 

 mon to two given conies or quadrics.' 



The next meeting of the Society is the 

 Summer Meeting, which will be held at 

 Northwestern University, Evanston, 111., in 

 the first week of September. 



F. N. Cole, 

 Secretary. 



THE GEOLOGICAL SOCIETY OP WASHINGTON. 



At the meeting of the Society on' April 23, 

 the first paper, 'Folded Faults in the Southern 

 Appalachian,' by Mr. Arthur Keith, began 

 with a statement of the typical Appalachian 

 faults, which are characterized by great length 

 and uniformity, high southeast dips, and anti- 

 clinal origin. Their planes are, for the most 

 part, slips nearly parallel to the bedding. 

 Next were described a group of faults whose 

 derivation from anticlines is less obvious and 

 whose planes are marked by great irregularity 

 in direction and dip. Their irregularity can 

 be ascribed to subsequent deformation, al- 

 though the evidence of that is not always 

 strong. These two classes of faults have 

 been well known for ten or twelve years. 



A third and most unusual class of faults 

 comprises those in which great deformation 

 by folding and faulting affected the fault 

 planes after they were formed. This has 

 given rise to extreme irregularity in direction 

 and dip of the fault planes, and has thoroughly 

 obscured their real nature. No trace of anti- 

 clinal origin appears and a section along a 

 straight line will intersect a given fault in 

 several places. A minimum measure of the 

 throw is thus readily obtained and varies from 

 fifteen to twenty miles. The evidence prov- 

 ing these faults consists in superposition of 

 Archean granite on Cambrian sediments, dis- 

 covery of fossils in some of the overlying 

 masses, the establishment of a sequence of 

 six or eight distinct formations, unconform- 

 ities of distribution along the fault planes, 

 and breccias and other direct evidences of 

 faulting. 



The position of the plane before folding can 

 be reconstructed from the sequence of the for- 

 mations against it in different places. There is 

 thus developed a low dip of the plane toward 

 the southeast in the nature of a shear plane 

 gradually traversing the formations. Begin- 

 ning on the northwest in the lower Silurian 

 Tellico, it passes down through all the inter- 

 vening formations into the Archean granite. 

 From this general fact, in connection with 

 numerous local details, it is inferred that the 

 fault resulted from a direct thrust by the 

 Archean granite. The deformation of the 



