二十世纪中叶以后 ,中、美寒武纪地层研究都有重大进展。三叶虫是寒武纪的重要化石 ,中、晚寒武世牙形石有显著的生物地层意义。二十世纪中叶国内研究寒武系的学者 ,认为北美寒武系与西欧及北欧的相似 ,与中国的差异较大。目前看来 ,北美东部斜坡相区的寒武系与西欧、北欧相似外 ,北美西部广大地区 (包括阿拉斯加、加拿大及美国境内的落基山等地区 ) ,分别与西伯利亚 ,蒙古西北部一些地区 ,及我国华北、东北南部及华南等地区的寒武系关系较近。北美西部Nevada及Utah等地也显示地台区及斜坡相区的不同。文内对两个地区早、中、晚寒武世地层内相同的属或种 ,分别进行对比。两地区属种相同的数目 ,由老到新逐渐增多。岩石方面 ,也有相似之处 ,如Pioche页岩和馒头组的岩性 ,NotchPeak灰岩与凤山组藻类灰岩及Hales灰岩与华北晚寒武世的竹叶状灰岩等 ,都有相似之处 After the middle of the twentieth century, great progress has been made in the research of the Cambrian strata between China and the United States. Trilobite is an important fossil of the Cambrian, and the Middle and Late Cambrian conodont has significant bio-stratigraphic significance. In the mid-twentieth century, scholars studying the Cambrian system in China considered that the North American Cambrian system is similar to Western Europe and Northern Europe, and differs greatly from China. At present it seems that the Cambrian of the eastern slope facies of North America is similar to western Europe and northern Europe. In most parts of western North America (including Alaska, Canada and the Rocky Mountains in the United States), they are respectively connected with Siberia, some areas in northwestern Mongolia, The relations between North China, South Northeast China and South China are close. Nevada and Utah in western North America have also shown differences in terrain and slope facies. The text compares the same genus or species within the Early, Middle and Late Cambrian strata in the two regions. The same number of species in both regions gradually increased from old to new. There are similarities in the rock. For example, the lithology of the Pioche shale and steamed bread groups, the Notch Peak limestone and the Fengshan Formation algal limestone and the Hales limestone, and the late Cambrian bamboo leafstone in North China, etc. are similar Where