div class=trans-pagebuttonPage 1button div class=trans-image amp-img class=trans-thumb alt=Page 1: Magnetic Polarity and Igneous Petrology src=https:reader030fdocumentsinreader030viewer2022020312575068341a28ab0f07af149bhtml5thumbnails1jpg width=142 height=106 layout=responsive amp-img divp© 1966 Nature Publishing Grouppdivdiv class=trans-pagebuttonPage 2button div class=trans-image amp-img class=trans-thumb alt=Page 2: Magnetic Polarity and Igneous Petrology src=https:reader030fdocumentsinreader030viewer2022020312575068341a28ab0f07af149bhtml5thumbnails2jpg width=142 height=106 layout=responsive amp-img divp© 1966 Nature Publishing Grouppdiv