You are correct, Laurie. The wider collars were usually late Victorian to early 20th Century - 1920's.....
The detectable collars were worn in the 1840s, 50s, and 60s as well. Lew Powell wore one as well - and the portrait of Powell in the prisoner's dock, drawn from life by General Lew Wallace illustrates young Powell wearing a detachable collar complete with collar button. He did not wear that blue flannel Navy jumper all the time apparently.