found in vernal pool along trail between Black Ance Rd. turnaround
and the McParlan House cabin. A dark coloured female Bull frog
was seen floating in the pond, working to remove some kind of membrane
that was wrapped around its head -- almost looked to me like the
remnants of a frog-egg mass.

However, I've just received an explanation from Wes von Papineau, responding on the NatureList:
"Amphibians, like snakes and lizard, intermittantly shed their outer epidermal layer
as part of their growth process. This 'sloughing' can be caused by growth,
rapid changes in their environment or in captivity, by stress.
It's a normal activitiy, and like snakes, the frog 'shines' for a few hours afterwards.
Sometime frogs (and newts) eat their skin after sloughing."

UTM 18T 0402587, 4958299; 12:09 hrs.