The Relations of the Crystalline Rocks of Eastern Pennsylvania to the Silurian Limestones and the Hudson River Age of the Hydromice Schists

Charles E. Hall
1880 Proceedings of the American Philosophical Society  
Known as the Early Journal Content, this set of works include research articles, news, letters, and other writings published in more than 200 of the oldest leading academic journals. The works date from the mid--seventeenth to the early twentieth centuries. We encourage people to read and share the Early Journal Content openly and to tell others that this resource exists. People may post this content online or redistribute in any way for non--commercial purposes. Read more about Early Journal
more » ... out Early Journal Content at http://about.jstor.org/participate--jstor/individuals/early-journal--content. JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people discover, use, and build upon a wide range of content through a powerful research and teaching platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not--for--profit organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please contact support@jstor.org. 1880.] 435 [Hall. 14. The continual reciprocal action" between attracting centres, (g oc -) o disturbances proportional to mass. 15. The limiting influence of parabolic velocities, upon tendencies to dissociation and to aggregation. 16. The ratio of stress-opposing force, at Laplace's limit, to parabolic (-2 )and to orbital (-r) velocity. The influence of centres of linear and of spherical oscillation. 18. The conjoint influence of centres of nucleation, of density, of nebulosity, of rotary inertia, and of reciprocity. 19. The equations of relation between oscillatory and orbital motion. 20. The interesting and suggestive FACT, important in chemistry and general physics as well as in astronomy, that the central stress-opposing value in the solar system ( ) is the velocity of light. The Relations of the Crystalline Rocks of Eastern Pennsylvania to the Silurian Limestones and the Hudson River Age of the Hydromice Schists. Recently Prof. Frazer called the attention of the Academy of Natural Sciences to the fact of the occurrence of the fossil Buthotrephis flexuosa in the Peach Bottom roofing slates of York county, Pennsylvania. As Prof. Lesquereux admits that this fossil does not extend below the Trenton limestone, it is in all probability within the Hudson river group. Dr. Emmons assigned this fossil to the Taconic System. Since Dr. Emmons' time, I think the fossiliferous bed of the Taconic system have been pretty well proven to be of the Cambrian series, which would place this Taconic fossil of Emmons somewhere about the Hudson river group. I embrace this opportunity to state some facts from which I have drawn conclusions concerning the relative positions of the rocks forming the crystalline series of Eastern Pennsylvania. I shall endeavor to make my statements concise, and I think my reasoning will be understood. We have the following series of rocks: First. A series of granitoid, syenitic, quartzose, and micaceous schistose rocks, to be seen on the Delaware river above the city bridge at Trenton, and extending in a south-easterly belt across Bucks and Montgomery counties, as far west as Chestnut Hill, Philadelphia. Second. A series of syenitic, hornblendic and quartzose rocks extending from the neighborhood of Chestnut Hill westward across the Schuylkill river, and covering a greater part of the northern portion of Delaware county. Fine exposures of this rock are to be seen on the Schuylkill river below Spring Mill, Montgomery county. This series may be the upper members of the first, or that extending from the Delaware river to Chestnut Hill. 1880.] 435 [Hall. 14. The continual reciprocal action" between attracting centres, (g oc -) o disturbances proportional to mass. 15. The limiting influence of parabolic velocities, upon tendencies to dissociation and to aggregation. 16. The ratio of stress-opposing force, at Laplace's limit, to parabolic (-2 )and to orbital (-r) velocity. The influence of centres of linear and of spherical oscillation. 18. The conjoint influence of centres of nucleation, of density, of nebulosity, of rotary inertia, and of reciprocity. 19. The equations of relation between oscillatory and orbital motion. 20. The interesting and suggestive FACT, important in chemistry and general physics as well as in astronomy, that the central stress-opposing value in the solar system ( ) is the velocity of light. The Relations of the Crystalline Rocks of Eastern Pennsylvania to the Silurian Limestones and the Hudson River Age of the Hydromice Schists.
fatcat:fhk75vze55hnnlrunjsjdxk2mu