The quote "" “Unitarianism [Wheeler's nominal religion] is a feather bed to catch falling Christians” (Darwin); "" is from not one, but two Darwin's.
Here is Charles Darwin quoting Erasmus Darwin in his own slant: https://cudl.lib.cam.ac.uk/view/MS-DAR-00115-00015/5
The source is a Charles Darwin ancestor, Erasmus Darwin. https://www.goodreads.com/work/quotes/566632-the-life-of-era...