proceedings: geological society 23 



regular peogram 



Edgar T. Wherky: Notes on the geology near Reading, Pennsylvania, 

 (Illustrated.) The Cambrian, Ordovician, and Triassic formations of 

 the region, and their structures, were briefly described. The Cambrian 

 comprises a quartzite and two limestones; the Ordovician, limestone, 

 cement-rock, and shale; and the Triassic, shale, sandstone, conglomerate 

 basalt, and diabase. The beds are greatly disturbed, being in places 

 overturned to 45°, elsewhere intricately folded, and cut by three systems 

 of faults: thrust-faults from the southeast, dating from late Ordovician 

 time; normal faults with the drop on the southeast, which formed dur- 

 ing the Triassic deposition; and normal faults crossing the other two sys- 

 tems nearly at right angles, which were "developed at the close of 

 Triassic time. 



Discussion: G. W. Stose referred to the remarkable amount of 

 faulting exhibited in this area. In an area 20-30 miles to the south, 

 whose structure had been worked out, there is almost none. He re- 

 marked also on the well-defined characteristics of the Martinsburg 

 shale in this section. In an adjacent section it is difficult to distin- 

 guish between the Martinsburg shale and certain shaly strata in the 

 Cambrian. 



J. W. Gidley: The relations of vertebrate fossils to stratigraphy. (No 

 abstract.) 



N. H. Darton: Some geologic features of southeastern California. 

 (Illustrated.) The results of a reconnaissance made near the line of the 

 Santa Fe Railroad from Needles to Cajon Pass in 1906 and 1914 were 

 outlined. Some of the facts have been published in the Guide Book to 

 Geology, etc., of the Santa Fe Railroad, but many technical details re- 

 garding rocks, structure, and fossils were necessarily omitted from that 

 publication. Six general series of rocks were found: (1) A widely ex- 

 posed basement of pre-Cambrian granites and schists, mostly appearing 

 in high ridges; (2) a succession of Paleozoic rocks which yielded Cam- 

 brian to Carboniferous fossils at several localities, notably in Iron 

 Mountain and its northern continuation, Providence Mountain, to 

 which a side trip was made from Kelso; (3) intrusive quartz-monzo- 

 nites and similar rocks cutting the Paleozoic strata and altering lime- 

 stones to marbles; (4) a thick series of Tertiary (Rosamond, etc.) vol- 

 canic rocks, largely breccia, tuffs, ash, and sediments, with interbedded 

 effusive sheets, and some intrusive masses; (5) the valley fill of the desert 

 plain, with lake beds and salt, gypsum, etc.; (6) recent volcanic cones 

 and flows, notably the very fine examples near Amboy and Pisgah. 

 Many details of structure were determined, but it was found that most 

 of the ridges and valleys were not closely related to faults as popularly 

 supposed. 



Discussion: F. C. Schrader inquired whether it was possible to make 

 correlations among the various volcanic series of different sections; also 

 as to the manner in which mineralization was associated with the igneous 

 rocks. Darton replied that the volcanic rocks of the younger series 



