Bandy和Arnal的早期研究是利用海底有孔虫古生态学绘制一系列描述加利福尼亚圣华金盆地第三纪中期历史的古等深线图。他们的结论是,原圣华金盆西南角部分地段业已消失,可能因圣安德烈斯断层带晚第三纪发生右旋滑动而移向它处。他们认为,消失的盆地碎块或许移向西北很远处即圣安德烈斯断层对面圣克鲁斯附近(图1) Earlier studies by Bandy and Arnal draw on a series of paleo-contour maps depicting the mid-Tertiary history of the San Joaquin Basin, California, using the paleoecological ecology of the submarine foraminifera. Their conclusion is that parts of the southwest corner of the original San Joaquin basin have disappeared and may have moved to the area due to the dextral slip of the San Andreas fault zone in the late Tertiary. In their view, the disappearing basin fragments may have moved far northwest of Santa Cruz near the San Andres Fault (Figure 1)