It looks like we had a few large orders that went through ... (I would put up a 'print screen' but I'm still at work)
10:26:21 0.0031 1,000,000
10:47:07 0.0028 1,376,668
10:49:01 0.0026 990,000
11:04:15 0.0031 1,340,000
11:33:27 0.003 3,500,000
The rest were fairly average order sizes. Also, there were a few times when some similar block sizes hit together at one price. Crooked MM's trying to disguise their orders most likely.