Does Google adsense cap hits

I have had a couple of days over the last couple of weeks where clicks on adsense have been over 50 today and 70 one day last week. And each day the pay has been ridiculously abysmally low. The type where you think why bother.

Todays earnings on the 50+ hits have come to a whole $1

Do they compare your average clicks then if things seem to be abnormal, cap what you earn?

I'm going to be altering the add code for each add location to try and track down, where the clicks are coming from on my forum over the next couple of days

Check out:
Inside AdSense: The facts about smart pricing