The super PACs supporting Newt Gingrich and Rick Santorum, the not-Romney candidates in the Republican presidential race, continued raising money in March as their candidates failed to cut into Mitt Romney's delegate lead.

The Red White And Blue Fund, the super PAC backing Santorum, raised $2.6 million in March. The money largely came from familiar sources: the talkative Wyoming investor Foster Friess, the oil tycoon William Dore, and Annette Simmons, the wife of Dallas industrialist and super PAC donor Harold Simmons.

Friess chipped in $500,000, bringing his total contribution to the super PAC to $2.1 million. Dore raised his total contribution to $2.25 million with an additional $750,000 in March. Annette Simmons pitched in $250,000 in March, on top of the $1 million she gave in February.

There were also new donors to help Santorum's last-ditch effort. Susan Gore, the scion of W.L. Gore & Associates, a multi-billion dollar industrial company best known for Gore-Tex waterproof fabric, gave $500,000. The investor and racehorse owner Kenny Troutt, previously a backer of Texas Gov. Rick Perry, gave $150,000. Chris Seipman, co-founder of The Liquid Capital Group, gave $250,000.

The super PAC backing Gingrich continued fundraising from pretty much its only source. Miriam Adelson, wife of casino billionaire Sheldon Adelson, gave $5 million to Winning Our Future, the pro-Gingrich super PAC, in March. That brings the Adelson family total to Gingrich's super PAC to $21.5 million.

While the pro-Santorum super PAC burned through nearly all of its money and Santorum has suspended his campaign, the pro-Gingrich super PAC ended March with more than $5 million cash on hand. It is not clear what the group will do with that money as Gingrich has essentially no path to the GOP nomination, even though he remains in the race.