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of fresh porphyritic rocks which extend westward from the town of East 

 Greenwich, although the Cambrian and Carboniferous sedimentaries and 

 the various Paleozoic igneous rocks of this difficult area are not neglected, 

 A complex collection of igneous rocks was intruded into the Cambrian 

 schists, in Carboniferous times or earlier, as a laccolithic mass. A narrow 

 basic border on the northern side of this mass passes on the south into a 

 broad band of the granitic nucleus, while still farther south are extensive 

 microgranites and graphic microgranites. The microgranites and the 

 basic rocks of the narrow border seem to be portions of a common mantle 

 over the granite. Fragments of the graphic microgranite in a blue quartz- 

 porphyry cement constitute a breccia in the central area. After the con- 

 solidation of the granite and the rocks of its mantle, microgranite dikes 

 penetrated the mass ; then an explosive eruption blew off this microgranitic 

 capping and furnished the numerous fragments of that rock found in the 

 adjacent Carboniferous conglomerate. A portion of the magma left in the 

 conduit solidified to form the central mass of porphyry; while another part, 

 already partially crystallized, cemented shattered fragments of the graphic 

 microgranite when a sudden transference to a higher level caused a rapid 

 consolidation. In the comparatively quiet period following this eruption, 

 the Carboniferous conglomerates containing bowlders of these igneous 

 rocks were spread still more widely over the region. The conglomerates 

 afterward suffered considerable metamorphism, so that their paste was con- 

 verted into a coarse muscovite schist and many secondary minerals were 

 developed. The publication of this bulletin will go a long way toward 

 clearing up the very complex geological history of Rhode Island. 



H. H. 



Some Principles of Seismic Geology. The Geotectonic and Geodynamic 

 Aspects of Calabria and Northeastern Sicily. By William 

 Herbert Hobbs. Sonderabdruck aus Gerlands Beitragen zur 

 Geophysik. Bd. VIII, Heft 2, s. 219-362. Leipzig: Wilhelm 

 Engelmann, 1907. 



The author of these two articles, in an endeavor to gain more light on 

 the crustal architecture of regions like the New England states, was on his 

 way to Calabria when the disastrous earthquake of 1905 occurred in that 

 province. His observations were thereby greatly facilitated. The first 

 monograph deals in a broad way with seismic phenomena and their relation 

 to certain geological problems. Data gathered from the communes damaged 

 by earthquakes leads to the conclusion that they are usually arranged along 



