UFO came down and went behind a hill 300 yards away.

In 1978 I witnesed a ufo while parking in the country side with a girl friend.  I looked up and saw a ufo and my jaw dropped.  
My girl friend kept saying whats wrong, whats wrong.  I couldn't speak only stare.  It was about 300 yards away and took 2 minutes to go down behind a hill.  
As soon as it disappeared behind the hill I told her I saw a ufo.  We drove down a dirt road trying to see it but the hill was in the way.  I was to afraid to get out and climb the hill.  To this day no body believes me.  
I remeber as it was just happening.  I can describe it and draw it.  It was deadly silent and as big as a house.  There were lights that went around it and pointed down as it began to descend below the hill.  I'm really serious....
Witness indicates that the date of the sighting is approximate.  PD