To the commissioners of the River Wear, and port and haven of Sunderland, in the county of Durham. The following essay, on the nature and quality of the stones that lay upon the shores and in quarries near the month of the River Wear, and port and haven of Sunderland; and an estimate of the expence of every particular part of the south pier intended to be erected at the entrance of the said port and haven, are most respectfully inscribed, by their engineer, and humble servant, Joseph Robson.