COSTA MESA – A group of atheists called Backyard Skeptics is planning to unveil a billboard at 1545 Newport Blvd., Wednesday afternoon with a quote from Thomas Jefferson bashing Christianity.

The quote reads, “I do not find in Christianity one redeeming feature. It is founded on fables and mythology.”

There’s one problem: There’s no evidence Jefferson ever said it. The Jefferson Library Collection at Monticello lists it on a page of spurious Jefferson quotes.

Bruce Gleason, whose group paid for this and other recent atheism billboards that have gone up in O.C. in recent months, said Wednesday he wasn’t sure about the origin of the quote.

He agreed that Monticello was an authoritative source.

“You’re absolutely right,” he said. “I should have done the research before I put my billboard up.”

The quote on the billboard is an abridged version of a quote that first appeared in a 1906 book called “Six Historic Americans,” by John E. Remsburg, who attributed it to a “Letter to Dr. Woods.”

It reads: “I have recently been examining all the known superstitions of the world, and do not find in our particular superstition (Christianity) one redeeming feature. They are all alike, founded upon fables and mythologies.”

The Jefferson Library knows of no letter to a Dr. Woods ever written by Jefferson, or of any appearance of the phrase anywhere in his writings.

On a page about spurious quotes attributed to Thomas Jefferson, the Jefferson Library writes: “We are asked about this one on a fairly regular basis. As with many spurious Jefferson quotes, it is frequently seen on various Internet sites. Many sites do not cite a source, but a good number of those that do attribute this quote to a letter from TJ to a ‘Dr. Wood.’

“As far as we know, TJ never wrote to an individual calling him/herself Dr. Wood. Another suspicious element is the statement that he does not find in Christianity ‘one redeeming feature.’ One presumes that Jefferson did, in fact, find some redeeming features in Christianity, otherwise he would not have taken the time to paste together his own versions of the Bible.”

Gleason said his group is pushing two goals: “To let other people, non-believers, know that there’s a place you can go and share the idea that you can be good and do good without a religion or god. And the second thing is that we want to expunge the myth that this is a Christian nation, the idea that the Declaration of Independence or Constitution have one ounce of Christian tenets.”

Foundation librarian Jack Robertson said a colleague who knew the material best was out of town, but that he reviewed the relevant sources.

“I do not see anything that suggests an alternative conclusion to be drawn, i.e., that this is a spurious Jefferson quotation,” he said.

Gleason said he would do some more research on the quote, although he didn’t think it misrepresented Jefferson’s views.

Jefferson was a Deist, who believed in a hands-off creator, not a Christian, but he adored the humanistic aspects of Jesus’ teachings, according to the library. A library report cites his letter to William Short of Oct. 31, 1819, in which he called the teachings of Jesus the “outlines of a system of the most sublime morality which has ever fallen from the lips of man.”

Gleason’s group got attention last month for tearing out pages of the Bible at Huntington Beach pier. It’s also gotten media coverage for billboards put up in Santa Ana, Garden Grove, and Orange recently, and in Westminster in May.

Similar billboards have gone up around the country as part of an effort by the United Coalition of Reason.

The new billboard will be unveiled at 4 p.m. Wednesday along a Newport Boulevard frontage road between Commercial Way and Industrial Way, in the parking lot of Recovery Morning.

Contact the writer: jcassidy@ocregister.com or 714-796-7922