major oil leak!

[PeterBergin at aol.com]

Hi guys, my 91 avant just sprung a major oil leak.  Car has always  been bone 
dry underneath. Spotted a small drip under the car before I left work  today, 
thought it was one of the PS hoses.  Drove home (about 20 miles) and  notice 
the oil pressure gauge bouncing around between 2.5 and 4 bar, (normally  5).  
Got home and was down two quarts, added and started the car,  notice al little 
lifter noise.  Oil is running out in a steady stream on  the front left side, 
above the pan gasket, near a sensor that is hard to see  behind some hoses.  
But definitely on the front left.
 
Any ideas?
 
Pete
91 Avant