Oh, that was so painful to watch as a C5 Z06 owner myself! Here is information from the article:
The painful losses have been tallied: Of the eight cars that fell, six were donated to the museum by Corvette enthusiasts, and two are owned by the car's maker, General Motors.
Here's the museum's list of cars that went down the hole:
-- a 1962 "Black Corvette"
-- a 1984 PPG pace car
-- a 2009 ZR1 "Blue Devil"
-- the 1992 white "1 Millionth Corvette"
-- a 1993 ruby red "40th Anniversary Corvette"
-- a 2001 Mallett Hammer Z06 Corvette
-- the 2009 white "1.5 Millionth Corvette"
-- a 1993 ZR-1 Spyder