In this section Udden refers this ammonite genera the Saptank (= Pennsylvanian) and on page 42 to the Wolfcamp (= Permian). The ammonites may look like Permian forms and yet the associated fossils are all Penn- sylvanian and not older than Cisur. There cannot be no unconformity at this place in the midst of the shales. Nor do I see the possibility of such until zone 27 is reached.