I25°30' 



46°I5 



46°00 



45°40 



Tillamook 

 Bay 



45°30 



Figure 2. Geologic map of study area (modified from Peterson et 

 al. 1986, see fig. 1) showing the location of the carbonate 

 chimneys (solid square) on the outer shelf. Note the thrust 

 boundaries between Juan de Fuca plate and Oregon margin 

 (solid barbs on upper plate) and between the accretionary 

 primsm (west) and the Eocene volcanics with overlying 

 younger basinal deposits (east) (dashed line open barbs). 

 Lined pattern is exposures of Miocene to Pliocene mudstone 

 and siltstone; DSDP drill site 176 (solid dot). Locations 

 of seismic reflection lines SP-104 and -106 (dashed lines). 

 Contours in meters. (After Schroeder et al. 1987). 



154 



