Our plane left the Ottawa River @ Rolfton heading NNW to our rendevous,a campsite on the Dumoine River.Ahead, we (pilot and myself)spotted a brilliant blue/white glow coming from the forested hills ahead,we altered course to investigate as this was an unpopulated area without road access,when we approached we saw a large glowing object approx.150 ft x80ft. oval in shape casting a glow similar to that of an arc welder,it was hovering above the southern tip of an unfamiliar lake,the area below this object was completely devoid of water,you could see the mud and rotten tree stumps stretching beyond the objects sides at least 20 or 30 ft.and the water in the remainder of the lake was held back as if a glass barrier had been installed from shore to shore a distance of approx.300 ft. The object sported a number of pink lights midway down its sides from our view directly above.It did not appear to notice our plane and we did a right bank,circled once and proceeded on our way as we were short of time,it was nearing dusk and we were not equipped with landing lights nor radio (vintage 1946 J3 cub) Pat made me promise not to disclose what we saw to anyone,he feared his pilots license would be jeopardized.Pat worked for ,he was a good friend he passed away a short while ago and I feel I no longer must keep this promise.I might add that upon our return to Deep River one week later his wife greeting us,said we had missed all the action,that UFO,s had been buzzing the AECL plant in Chalk River all week,I have never seen anything that would attest to this but it should not be too much of a problem for you to find this out ,it would then give an exact date for our encounter