Most people think of rear suspension bikes as being a mid 1990's invention but here is one from a full decade earlier......even 5 years before the first commercially available front suspension forks!  There was an early school of thought that believed rear suspension was more important than front suspension.  The front of the bike could be steered around or lifted over trail obstacles while the rear hit everything.  Mountain Cross Racing was one of the earlier companies to produce these rear suspension bikes starting in 1984.  It appears as if the bikes were produced into 1987 with minimal differences.