A Survey of Significant Locations in England and Wales by Henry Boatright

Cabot Tower, Brandon Hill, Bristol : thanks to Wikipedia 

Title: A Survey of Significant Locations in England and Wales

Author: Henry Boatright

Publisher: Not known but printed in 1907

Source Book: Foxglove Summer by Ben Aaronovitch (Rivers of London #5)

Henry Boatright surveyed Earthworks and Ancient Monuments for vestigia (signs of magic) and, where possible, included information provided by reputable practitioners (magicians). Peter Grant finds a copy of Boatright’s book A Survey of Significant Locations in England and Wales in Hugh Oswald’s library. This particular copy has the distinctive burgundy cloth binding associated with limited editions published in Oxford specifically for The Folly.

Boatright is an unspeakably dull writer but he lists Croft Aubrey, Brandon Hill, Pyon Wood Camp and the battlefield at Mortimer’s Cross; all useful for Peter’s investigation.

Also in Hugh Oswald’s library, Peter finds a tatty copy of Histoire Insolite et Secrète des Ponts de Paris by Barbey d’Aurevilly. 

This is the Rivers of London book where Peter becomes the father of a small river in Herefordshire. Possibly.

Pyon Wood Camp Hillfort: thanks to The Modern Antiquarian.com