IV. The monumental marks by which the said boundary line, except such portions thereof as may be within the waters of the Delaware river, and Lake Erie, shall hereafter be known and recognized, are hereby declared to be:--

I. The original monuments of stone, erected in the years 1786 and 1787 by the commissioners aforesaid, and in the year 1790 by Andrew Ellicott aforesaid, as the same have been restored and re-established in their original positions, or have been replaced by granite monuments erected in the years 1881, 1882, 1883, 1884 and 1885, by H. Wadsworth Clarke, surveyor on the part of New York, and Christopher M. Gere, surveyor on the part of Pennsylvania, duly appointed by the parties hereto.