Figure 23. Paleomagnetic data plot and stratigraphic column at Mesa Portales, southeastern San Juan Basin, New Mexico (locality on Figure 21). Stratigraphy of section from Fassett (1966) and Fassett and Hinds (1971). Palynomorphs from rock samples from this section identified by R.H. Tschudy (personal commun., 1966, 1967, 1968, 1983, 1984); palynomorphs identified in tables in Appendix. Paleomagnetic data plot provided by M.B. Steiner (personal commun., 1992). Samples for Mesa Portales paleomagnetic study were collected by E. M. Shoemaker, M.B. Steiner, and the author in 1983 and 1989; lab analyses of samples were conducted by Steiner and Shoemaker. On paleomagnetic column, full column width indicates latest Cretaceous-earliest Paleocene magnetization; two-thirds column width indicates probable latest Cretaceous-earliest Paleocene magnetization. An annotated photograph of section is Figure 22. Cretaceous index palynomorph Tschudypollis was originally named Proteacidites.