There is one identifiable group of Purseys in Devon – those found in and around Hemyock, Culmstock and Uffculme. Earliest identifiable are William, John and Joan all born in the 1770s to John and Ann (unknown). There are a number of other short lines on the Devon Purseys tree – most likely all related.
The presence of Jane Herniman/Horniman, wife of blacksmith William Pursey, suggests they might come from Taunton. (The 1837 will of builder George Herniman of Taunton (died 1842) bequeaths his son Robert “all with premises are situate in East Reach in Taunton aforesaid and are now by the name of Late Purseys”. (This is likely to be the house of Hannah Pursey (Edmonds)). A comple transcript of George Herniman’s will can be found here on Roy Parkhouse’s excellent site.
It must be said that identifying early forebears is extremely difficult. Besides Pursey, there are numerous individuals identified as Perc(e)y (from Inwardleigh and Lamerton) and Persey (Kentisbeare). In addition, the name Piercy (and its variations – Pierc(e)y, Pear(c/s)ey) are common in the county. So beware!