diff --git a/openmc/cell.py b/openmc/cell.py
index 0cea73b32..d03052623 100644
--- a/openmc/cell.py
+++ b/openmc/cell.py
@@ -650,7 +650,7 @@ class Cell(IDManagerMixin):
         surfaces : dict
             Dictionary mapping surface IDs to :class:`openmc.Surface` instances
         materials : dict
-            Dictionary mapping material IDs to :class:`openmc.Material`
+            Dictionary mapping material ID strings to :class:`openmc.Material`
             instances (defined in :math:`openmc.Geometry.from_xml`)
         get_universe : function
             Function returning universe (defined in
diff --git a/openmc/geometry.py b/openmc/geometry.py
index d036df9c7..57aab1884 100644
--- a/openmc/geometry.py
+++ b/openmc/geometry.py
@@ -256,9 +256,9 @@ class Geometry:
         ----------
         path : str, optional
             Path to geometry XML file
-        materials : openmc.Materials or None
-            Materials used to assign to cells. If None, an attempt is made to
-            generate it from the materials.xml file.
+         materials : dict
+            Dictionary mapping material ID strings to :class:`openmc.Material`
+            instances (defined in :math:`openmc.Geometry.from_xml`)
 
         Returns
         -------