Figure 30. Cross section showing five magnetic-polarity columns containing chrons C33n and C32r in the southern San Juan Basin; datum is C33n-C32r reversal. Figure 1 shows column localities. Column HW/AW from Lindsay et al. (1981), columns MM and EM from Butler and Lindsay (1985), column HW from Fassett and Steiner (1997), and column MP is published herein for the first time. This figure is modification of Figure 29.