Paleomagnetic data were obtained from 22 sites (6–10 samples/site) in the Upper Shale Member of the Chinle Formation, 43 sites in the Owl Rock Member of the Chinle Formation, and 35 sites in the Kayenta Formation. Thermal demagnetization and data analyses indicate that within‐site dispersion is an important criterion for selecting sites which retain a high unblocking temperature characteristic remanent magnetization (ChRM). Site‐mean directions define at least four antipodal polarity zones within each member/formation, suggesting the ChRM was acquired soon after deposition. Fifteen site‐mean virtual geomagnetic poles (VGPs) from the Upper Shale Member of the Chinle Formation yield an early Norian paleomagnetic pole position of 57.4°N, 87.8°E (K = 60, A95 = 5.0°). Eighteen site‐mean VGPs from the Owl Rock Member of the Chinle Formation yield a middle Norian paleomagnetic pole position of 56.5°N, 66.4°E (K = 183, A95 = 2.6°). Twenty‐three site‐mean VGPs from the Kayenta Formation yield a Pliensbachian pole position of 59.0°N, 66.6°E (K = 155, A95 = 2.4°). Combined with paleomagnetic poles from the Moenave Formation and the Shinarump Member of the Chinle Formation, these data record ∼30 m.y. of North American apparent polar wander (APW) within a regional stratigraphic succession. During the Camian and Norian stages of the Late Triassic, Chinle poles progress westward. During the Hettangian through Pliensbachian stages of the Early Jurassic, the pattern of APW changed to an eastward progression. Even after correction for 4° clockwise rotation of the Colorado Plateau, a sharp comer in the APW path (J1 cusp) is resolved near the pole from the Hettangian/Sinemurian (∼200 Ma) Moenave Formation (59.4°N, 59.2°E). Amongst other implications, the sharp change in the APW path at the J1 cusp implies an abrupt change from counterclockwise rotation of Pangea prior to 200 Ma to clockwise rotation thereafter.

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The paleomagnetism of the ∼147 Ma (Tithonian) Brushy Basin Member of the Morrison Formation was analyzed to obtain a Late Jurassic paleomagnetic pole for North America. A total of 200 samples were collected from 25 sedimentary horizons (sites) at Norwood Hill in southwest Colorado. At Montezuma Creek in southeast Utah, 184 samples were collected from 26 sites. Detailed thermal demagnetization (up to nine temperature steps between 600°C and 680°C) and principal component analysis were required to confidently isolate characteristic remanent magnetization (ChRM) directions carried by hematite. Demagnetization behavior for many horizons is erratic and does not allow isolation of a high unblocking‐temperature ChRM. Data selection criteria required sample ChRM directions to be defined by three or more thennal demagnetization steps and maximum angular deviations of sample ChRM directions to be ≤20°. Eight sites from the Norwood Hill location and 10 sites from the Montezuma Creek location passed these criteria. The 18 site‐mean virtual geomagnetic poles yield a paleomagnetic pole position from the Brushy Basin Member of 68.3°N, 156.2°E (A95 = 4.8°, K = 53). This pole position is within 2° of the paleomagnetic pole which Steiner and Helsley (1975a) reported for the “upper” Morrison Formation at Norwood Hill, Colorado. A second paleomagnetic pole was calculated after excluding sites with site‐mean α95 > 20° and sites with fewer than three samples that passed the above selection criteria. This additional editing did not significantly change the paleomagnetic pole position at the 95% confidence level. Along with other paleomagnetic poles from the continental interior the paleomagnetic data from the Brushy Basin Member of the Morrison Formation are interpreted to indicate that the Late Jurassic part of the North American apparent polar wander path progresses from a late Middle Jurassic (∼160 Ma) position at ∼60°N, 135°E toward the mid‐Cretaceous pole position at 72°N, 191°E.

Jurassic through Paleocene rocks of the Methow–Pasayten belt were studied in order to use paleomagnetic directions to resolve the question of Cretaceous northward transport. In the end, circumstances prevented us from doing so. However, three independent studies of these rocks, summarized here, indicate that several units retain strong and stable magnetizations that are different from the present axial dipole field direction. When partly or completely corrected to paleohorizontal, these magnetizations become less dispersed, suggesting that they were acquired before at least the last stage of Late Cretaceous deformation. A pervasive northeast–southwest streak of magnetizations at various stages of structural correction indicates that at least some of the rocks were partly to completely remagnetized at different times during folding. This complex structural–remagnetization history and consequent loss of paleohorizontal prevent a simple analysis of paleolatitude during remagnetization. However, analysis of the youngest layered rocks of the Goat Peak syncline indicates that much of the remagnetization occurred when the structure was more open but still well developed. Subsequent tighter folding followed intrusion of the Fawn Peak stock. Our results are a useful case study of some of the problems that arise in studying the paleomagnetism of a complicated orogenic terrane.