This photograph was taken in Edinboro, Pennsylvania by the photography studio W. H. VanDyke & Son. Unfortunately there is no identifying information for this wonderful lady.
I suspect that the photography studio was owned by William H VanDyke of Edinboro, Erie, Pennsylvania. I was able to find him in the 1880 U.S. census, listed as an “artist.” He died sometime between 1880 and 1900, as his widow was found in the 1900 census living in Buffalo, Washington, Pennsylvania with her son Henry.
Sources
1880 U.S. Federal Census; Edinboro, Erie, Pennsylvania; Roll T9_1128; Page: 11; Enumeration District: 157.
1900 U.S. Federal Census; Buffalo, Washington, Pennsylvania; Roll T623_1493 Page: 9B; Enumeration District: 118.
I would think someone at the historical society there in Edinboro could give you a better time reference. My ‘Van Dykes’ all have the studio name on the front- see http://farm4.static.flickr.com/3149/3042694452_cfb8979b56.jpg for an example.