The Collaborative International Dictionary of English v.0.48:

Ignorantly \Ig"no*rant*ly\, adv.
   In a ignorant manner; without knowledge; inadvertently.
   [1913 Webster]

         Whom therefoer ye ignorantly worship, him declare I
         unto you.                                --Acts xvii.
                                                  23.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ignorantly
    adv 1: in ignorance; in an ignorant manner; "they lived
           ignorantly in their own small world"