A friend prompted me to find the significance of the design of that gift from Virginia'a daughter. Doing general searches about CANTERBURY were too broad. Then I tried the Latin words: Ave Mater Anglia. That did it. It is the coat of arms of the City of Canterbury. Here is the description given of the images on the shield.
THE CITY COAT OF ARMS
The full Coat of Arms of Canterbury carries a Golden Crown [of King Canute*] above the Shield. The "Golden Lion of England" is at the top of the Coat of Arms on a scarlet background. The three black birds are Cornish Choughs, who have red legs and red beaks. At the end of the 1800's, the City Council adopted the words "Ave, Mater Anglia"--"Hail, Mother of England"--and this is now on a scroll at the bottom of the official Coat of Arms.
*King Canute was an ancient Christian Danish ruler of Kent.