Large delta shape craft passed overhead blocking out the view of stars behind its shape. No sound.

At the time of this sighting I was a boy of twelve years of age. I was with a group of YMCA members camping overnight in the Tehachapi Mountians east of Mojave.
We were camped in the open, I had a clear view of the sky overhead through the trees.
We had all turned in for the night, I could not sleep. I was looking up when I noticed stars disappearing, something was passing by in the night sky in the shape of a huge delta shape. There were no running lights, I remember what was even stranger to me is that this craft made no decernable sound. It passed by my field of vision in about 15 seconds. Its direction was to the west. It did not seem to be moving very fast, I could not determine its speed as I could not figure how high or how large the craft was. This was really the highlight of my summer that year.
((FOLLOW-UP COMMUNICATION))
Peter,
Guess I screwed up, wrote this about 2 AM.
That's Tehachapi California.
I thought sometime later, what I saw may have been one of the two XB-70's that may have been flying about that time, but they never flew without a F-104 or A4 chase plane and I doubt they flew at night.. Those planes were very loud. 
I'm not one to believe in extra terrestrial UFO's because of the physics involved......but never say never.
Anyway, hope this helps. I found a couple of spelling gaffes as well. Oh well.
((name deleted))
((END COMMUNICATION))
Date is approximate.  PD