Enormous dark craft very slowly and quietly crossed sky overhead from east to west

When I was 16, we lived on a gravel road seven miles northeast of Mansfield, far from street lighting and most stray light pollution. It was particularly dark that night, no moon or new moon.  The atmosphere was especially clear and the stars were brilliant from horizon to horizon. Many of the neighborhood kids were congregated in the road in front of our home talking when I noticed that all of the stars on the eastern horizon began to 'wink' out.  Thinking it might be a cloud system moving in, I continued watching.  The object was moving slowly yet too quickly to be a cloudbank.  There was no wind or breeze.  As it approached overhead, we could make out only five, dim white lights stretching out north to south along the bottom of the craft.  It passed overhead, silently and steadily, and continued until it disappeared over the western horizon. The entire incident took maybe five minutes.  We were all asking each other if we could make out a shape, but because of the inky black sky, none us could make out any perceptible shape.  It was enormous however, based on the large expanse of starlit sky that it covered.
Date is approximate.  We have assigned an arbitrary date of June 15, so that the report posts to 1978.  PD