LITTLE ROCK — Supporters of a proposed initiated act that would raise the state severance tax on natural gas from 5 percent to 7 percent failed to submit enough valid signatures to place the measure on the Nov. 6 general ballot, the secretary of state’s office said Thursday.

They have 30 days to make up a more than 41,000-signature deficiency, though Sheffield Nelson, the former gas company executive who is spearheading the drive, was uncertain whether the effort would be made.

"I’ve never quit on anything, so my commitment is to go forward, but I want to make sure that everybody shares that commitment and not have me out there going down the road by myself," Nelson said.

He said he met with some supporters Thursday and would meet with others Friday and made a decision by Monday.

The Committee for a Fair Severance Tax submitted 69,717 signatures, of which 21,347 were valid signatures of registered voters, a spokesman for Secretary of State Mark Martin said.

The group needs 62,507 valid signatures to qualify the proposal for the ballot.

Along with meeting with backers of his proposal, Nelson said he also plans to re-evaluate the signature collection groups that helped circulate petitions.

"We had what we thought was a good group, but the production of valid signatures did not back that up," he said. "We’ll have to re-evaluate everything."

Nelson’s committee has raised $155,000, including $50,000 from North Little Rock businessman Frank Fletcher, and $100,000 from Calfneck Capital Corp. of Perryville, which is headed by Buddy Metcalf. The committee has spent about $70,000 on advertising and for canvassing, according to reports filed with the state Ethics Commission.

Arkansans For Jobs and Affordable Energy , an Arkansas State Chamber of Commerce-led group formed to oppose Nelson’s severance tax hike, has raised nearly $1.8 million, the bulk of it from Southwestern Energy, Stephens Production Co. and XTO. It has spent $1.6 million.

Supporters of a proposed initiated act that would legalize marijuana in Arkansas also came up short in their signature collection, the secretary of state’s office announced last week. Arkansas for Compassionate Care also was given an additional 30 days to gather signatures.