We're members of the Canning History Project and have found your website to be an amazing source of information.
Unfortunately we have discovered a mistake in the attribution of the 1769 map of Toxteth as being the site of the quarry which became St James Cemetery. The map is actually taken from the tithe map of Toxteth Park, and the quarry shown is actually on the current Mill Street in the area of Warwick and Northumberland Streets. The dammed pool is on the east side of Park Road in the region of Upper Warwick Street, and the water course flowing into it seems to follow the present Upper Warwick Street from the Mulgrave Street area.
We have a photocopy of this map, which is of Toxteth Park but not the Canning area (it was a handout from Ron Cowell of Liverpool Museums on a history walk). If it would be useful I can scan this and send it to you (from another computer as we are having some techy issues with this one). Keep up the otherwise excellent work.
Janet Ormrod & David Bateman.