I personally think it's due to the fact that a lot of people have been playing both of these based on 'Market Trends'.
The hurricane watch for Florida prompted fears about domestic oil (See HEC down $0.04) and some of those people are looking for foreign oil plays.
Also, a huge chunk of the people who normally wouldn't play such high-risk stocks, who bought NDOL on buyout news, finally had enough and sold.
In a feat of stock market-darwinian-evolution, now only the investors with strong stomachs are still around and are providing the base on which to build.