8  CONTENTS. 
Page. 
Chapter  XII.  Isolated  areas  in  the  Mississippi  Valley 717 
Section  1.  Wisconsin 717 
Baraboo * 717 
Summary  of  literature 717 
Summary  of  present  knowledge 720 
Waterloo,  Portland,  and  Lake  Mills 721 
Summary  of  literature _ 721, 
Fox  River  Valley 722 
Summary  of  literature 722 
Summary  of  present  knowledge 723 
Necedali,  North  Bluff,  and  Black  River 723 
Summary  of  literature 723 
Summary  of  present  knowledge 724 
Section  2.   Sioux  quartzite  of  contiguous  portions  of  Minnesota,  South 
Dakota,   and   Iowa 724 
Summary  of  literature 724 
Summary  of  present  knowledge 726 
Section  3.  Black  Hills  of  South  Dakota 727 
Summary  of  literature 727 
Summary  of  present  knowledge 732 
Section  4.  Missouri - 733 
Summary  of  literature 733 
Summary  of  present  knowledge 740 
Section  5.  Oklahoma 741 
Summary  of  literature 741 
Summary  of  present  knowledge . 742 
Section  6.  Texas 742 
Summary  of  literature 742 
Summary  of  present  knowledge 748 
Notes 749 
Chapter  XIII.  The  Cordilleras , 754 
Section  1.  Mexico  and  Central  America 754 
Summary  of  literature 754 
Summary  of  present  knowledge  of  Mexico 755 
Location,  importance,  and  character  of  pre-Cambrian  areas.  755 
Apparent  discontinuity  of  an  Archean  belt 750 
Mexican  pre-Cambrian  rocks  must  be  Archean 756 
Tectonic  importance  of  the  Archean  belt 756 
Petrographic  character  of  Archean  areas 759 
Insignificance  of  well-known  Paleozoic  sediments  in  Mexico 
at  present 760 
Lower    California 761 
Sonora  and  Sinaloa ■ 762 
Jalisco  763 
Guerrero  763 
Oaxaca,  Puebla,  and  Chiapas 765 
Section  2.  New  Mexico,  including  part  of  the  Front  Range  of  south- 
ern Colorado *_ 768 
Summary  of  literature 768 
Summary  of  present  knowledge 771 
Section  3.  Arizona  and  adjacent  parts  of  Nevada 771 
Summary  of  literature 771 
Summary  of  present  knowledge 777 
