Durgin marks by date?

[SnoodinOrange]

I had a question about the Durgin marks found on this site:
http://www.925-1000.com/americansilver_D2.html

Does anyone know the dates of the various types? I know the bird in the wreath is late 1800s, and the script D I read an estimate from 1888 to the 1930s, but the one with the clover or flower shown on the site - is it before the bird or simultaneous?
I have a few Durgin pieces in our small collection and would like to know more about the various marks.

[dognose]

There is book published regarding the Durgin company; William B. Durgin Co., Family Genealogy and Durgin Company History by Robert M. Wilhelm, published in 2014. I have not read it myself, but it may possibly contain such information.

Trev.

[SnoodinOrange]

Thanks very much! I'm just building my reference library and will try to track this book down. Much appreciated for the recommendation!