New York, Sep 9 (IANS/EFE): A letter from Charles Darwin in which he made it clear he did not believe in the Bible will be auctioned on September 21 in New York, Bonhams said.

The estimated opening price for the document, dated November 24, 1880, is between $70,000 and $90,000.

Darwin wrote the letter in answer to a young lawyer, Francis McDermott, who wanted to know if he believed in the New Testament, and asked him to respond with a "yes" or a "no", while promising not to make his reply known to anyone.

The English naturalist answered: "I am sorry to have to inform you that I do not believe in the Bible as a divine revelation, and therefore not in Jesus Christ as the son of god."

Darwin (1809-1882), as the auction house recalled in a communique issued on Tuesday, studied theology at Cambridge.

It was one of his professors, John Henslow, who urged him to go on the long voyage that inspired his great contribution to evolutionary theory, "The Origin of Species".

He was always reluctant to speak publicly about religion. The letter he wrote to McDermott was not made public until a century after Darwin sent it to him.

The document, with the personal letterhead of the naturalist and signed "Ch. Darwin", is the most important of the 78 lots up for bidding at Bonhams' History of Science and Technology sale on September 21.

Also to be auctioned will be another letter that the author of the theory of evolution sent to a member of The Geological Society in London about the research he carried out on his voyage aboard the HMS Beagle, with an initial estimated value of between $9,000 and $12,000.

Bonhams will also offer another manuscript, a photo of Darwin and a first edition printed in the US in 1860 of "The Origin of Species", with an opening bid of between $1,000 and $1,500.