The Pennsylvanian Quakers advised their members against the trade in 1696; in 1754 they issued to their brethren a strong dissuasive against encouraging it in any manner; in 1774 all persons concerned in the traffic, and in 1776 all slave holders who would not emancipate their slaves, were excluded from membership. The Quakers in the other American provinces followed the lead of their brethren in Pennsylvania.
A Pennsylvanian society was formed in 1774 by James Pemberton and Dr Benjamin Rush, and in 1787 (after the war) was reconstructed on an enlarged basis under the presidency of Franklin.
At the outbreak of the Civil War in 1861 he was employed on staff duties in the eastern states, and rendered great assistance in the organization of Pennsylvanian volunteers.
This older classification, which has little support except that which is traditional, is still adhered to by many geologists; hut the fact seems to be that the system is set off from the Pennsylvanian (Upper Carboniferous) more sharply than the Cambrian is from the Ordoviciao, the Silurian from the Devonian, or the Devonian from the Mississippian.
The explanation of the apparent conformity of the strata from the Cambrian to the Pennsylvanian in some parts of the west, with no fossils defining with certainty any horizon between the Ordovician and the Mississippian, is one of the open problems in the geology of the United States.