Public Database of Geologic Formation Ages?

[Saint Abyssal <saint_abyssal@yahoo.com>]

I'm having a surprising amount of trouble finding precise ages for geologic 
formations. Is there a public database available with the ages of a significant 
number of stratigraphic units? I'm creating timelines for Wikipedia showing the 
duration of times represented by different units but having to hunt down ages 
for each one is exhausting. Worse, I'm having trouble finding exact numbers for 
many units. I understand the gist of say, "late Maastrichtian" but I need exact 
numbers to enter into the timeline template and to enter guesstimates as to 
what exact numbers the authors meant by this would violate Wikipedia's policy 
forbidding original research.

Are there any resources that might help?

~ Abyssal