You have identified:

Canada Lily
(Lilium canadense)

© USDA, NRCS 
  http://plants.usda.gov
© knps.org/Wildflowers/ canada.htm

General Information: Canada lily is a perennial found in meadows and swamps.  A member of the Lily family, it is also known as the meadow lily or wild yellow lily.  Leaves are lance-shaped, usually in whorls, and are rough to the touch on the veiny underside.  Petals and sepals are spreading or partly curled backward.  Flowers are nodding and vary in color and shape.  The most common form an open, spotted, yellow bell.  Red and orange flower forms occur as well and bloom late June to early July.

Gleason, H. A.  1952.  The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada.  3 vols.  New York: Hafner Press.

Newcomb, L.  1977.  Newcomb's Wildflower Guide.  Boston: Little, Brown, and Company.

Rhoads, A.F. and Block, T.A.  2000. The Plants of Pennsylvania:
An Illustrated Manual. Philadelphia: University of Pennsylvania Press.