Much of the material in both volumes is printed in Charter to William Penn, and Laws of the Province of Pennsylvania . . . (Harrisburg, 1879). The first volume, prepared possibly for James Logan, contains copies of Charles II's grant to William Penn of the Lower Counties, 1683, an act of the Privy Council, 1705, the charter of Pennsylvania of 1701, acts of the Assembly, 1682-1719.

Three volumes contain letters, laws, charters, reports, proclamations, petitions, and other official and semi-official documents relating principally to early Pennsylvania and New Jersey, signed by or addressed to William Penn, among others. A fourth volume is Penn's cash book, 1699-1703, which records expeditures, payments of quit rents, etc. Tipped in is "Catalogue of Goods left at Pensbury," and of goods left at Philadelphia, 1701.

A pioneer in ethnographic and linguistic studies of the American Indian and one of the most active members of the American Philosophical Society, Peter Stephen Du Ponceau helped to establish the American Philosophical Society's reputation as one of the world's foremost centers for the study of American Indians and their languages. The Peter Stephen Du Ponceau collection consists of correspondence on legal matters, Indian linguistics, silk culture, maritime law, the American Philosophical Society, and various publications of the early nineteenth century. The collection also includes several essays by Du Ponceau, most of which deal with maritime law.