“When my co-authors go to their churches on Sunday, they have a lot of people in middle ground who want to know the truth but don't know which way to turn, the pastor or the park ranger,” he said.

Both Hill and Ranney said they know of no other book that has directly confronted the Young Earth Creation view of the canyon’s formation. In fact, geologists have long avoided doing so in public forums, to the detriment of science, they said.

“The whole geologic community in the 1970s and 1980s never engaged the topic of creationism and that’s how we got where we are. Creationist literal biblicists were the only ones addressing the idea of how Earth was created while geologists were just talking among themselves,” Ranney said. “We've stepped out of our comfort zone of our tribe to actually tackle the issue. Now we know that our disengagement previously has led to this place where so many people don't understand why we think the Grand Canyon is old.”

The book aims to promote the idea that Christianity and a Grand Canyon formed by millions of years of erosion are not mutually exclusive, Ranney said.

“It’s not antagonistic, it’s not attacking, it’s telling people that it is okay to be a believer and to believe the Grand Canyon is old,” he said.