The basal portion (further from lumen) of an intestinal crypt. Contains multipotent stem cells. Stem cells in the crypts divide to form daughter cells. One daughter cell from each stem cell division is retained as a stem cell. The other becomes committed to differentiate along one of four pathways to become an enterocyte, enteroendocrine cell, goblet cell or Paneth cell. [ http://purl.obolibrary.org/obo/UBERON_md http://orcid.org/0000-0002-6601-2165 ]