To get a pretty good sense of marie Corelli's unorthodox Christian beliefs, take a peak at this article: http://www.victorianweb.org/authors/corelli/religion1.html#carlyle. Her views are seen quite openly in one of her works, The Master-Christian:
"A church is a building more or less beautiful or ugly as the case may be, and in the building there is generally a man who reads prayers in a sing-song tone of voice, and perhaps another man who preaches without eloquence on some text which he utterly fails to see the true symbolical meaning of. . . . But as matters stand I am not moved by the church to feel religious. I would rather sit quietly in the fields and hear the gentle leaves whispering their joys and thanksgivings above my head, than listen to a human creature who has not even the education to comprehend the simplest teachings of nature, daring to assert himself as a teacher of the Divine. My own chief object in life has been and still is to speak on this and similar subjects to the people who are groping after lost Christianity. They need helping, and I want to try in my way to help them."
Although much of her criticism in this novel is aimed at the Catholic church, she is known to have criticized the Protestant church as well. Mainly, however, she was opposed to the hierarchical system within the church, and the institutionalization of Christianity.