Plate 2 _ Bedrock Geology

The bedrock map depicts the type, distribution, and structure of the Phanerozoic and Precambrain bedrock units in Yellow Medicine County, Minnesota that either are exposed at the land surface or lie directly beneath unconsolidated Quaternary sediments of variable thickness. The map shows how the bedrock surface would appear if it were viewed from an aerial perspective and the overlying Quaternary sediments were stripped away.本基岩图（bedrock map）描绘了美国明尼苏达州（Minnesota）黄药县（Yellow Medicine County）内显生宙（Phanerozoic）与前寒武纪（Precambrian）基岩单元的类型、分布与构造：这些基岩要么裸露于地表，要么直接赋存于厚度不均的未固结第四纪沉积物（unconsolidated Quaternary sediments）之下。本图展示了以航空视角（aerial perspective）观测并剥除上覆第四纪沉积物时，基岩表面所呈现的实际样貌。