192  BIBLIOGRAPHY    OF    NORTH    AMERICAN    GEOLOGY 
Keyes  (Charles  Rollin) — Continued. 
2.  Origin  and  classification  of  ore  deposits. 
Am.  Inst.  Mg.  Engrs.,  Trans.,  vol.  30,  pp.  323-356, 1901. 
Discusses  the  nature  of  ore  deposits,  general  methods  of  ore  formation,  the  classification  of 
ore  deposits,  and  certain  other  phases  of  ore  deposits. 
3.  Derivation  of  the  terrestrial  spheroid  from  the  rhombic  dodecahedron. 
Jour.  Geol.,  vol.  9,  pp.  244-249,  1901. 
Discusses  Green's  hypothesis  of  the  tetrahedral  form  of  the  earth. 
4.  Composite  genesis  of  the  Arkansas  Valley  through  the  Ozark  highlands. 
Jour.  Geol.,  vol.  9,  pp.  486-490,  2  figs.,  1901. 
Discusses  the  evidences  which  indicate  that  there  has  been  but  one  uplift  in  the  region  and 
that  the  river  eroded  its  bed  as  fast  as  the  strata  were  raised. 
5.  Ore  formation  on  the  hypothesis  of  concentration  through  surface  decomposition. 
Am.  Geol.,  vol.  27,  pp.  35V362,  1001. 
Discusses  the  evidence  as  to  the  derivation  of  the  lead  and  zinc  ores  of  the  Ozark  region  and 
their  bearing  on  the  origin  of  ore  deposits  in  general. 
6.  Nomenclature    of    the   Cambrian    formations    of    the    St,    Francois    Mountains 
[Missouri]. 
Am.  Geol.,  vol.  28,  pp.  51-53,  1901. 
Discusses  the  validity  of  certain  names  applied  to  the  Cambrian  formations  of  the  region. 
7.  A  schematic  standard  for  the  American  Carboniferous. 
Am.  Geol.,  vol.  28,  pp.  299-305,  1  fig.,  1901. 
Presentsa  general  section  of  the  Carboniferous  of  the  Mississippi  Valley  and  discusses  its 
correlation  with  other  regions. 
s.  Time  values  of  provincial  Carboniferous  terranes. 
Am.  Jour.  Sci.,  4th  ser.,  vol.  12,  pp.  305-309,  1  fig.,  1901. 
■    Discusses  the  time  ratios  of  the  several  subdivisons  of  the  Carboniferous  of  the  Mississippi 
Valley  region. 
9.  Note  on  the  correlation  of  the  Clarinda  well  section  with  the  schematic  section  of 
the  Carboniferous. 
Iowa  Geol.  Surv.,  vol.  11,  pp.  461-463,  1901. 
Compares  the  well  section  with  the  general  section. 
LO.  A  depositional  measure  of  unconformity. 
Abstract:  Science,  new  ser.,  vol.  13,  pp.  135-136,  L901. 
11.  On  a  crinoidal  horizon  in  the  Upper  Carboniferous. 
Science,  new  ser.,  vol.  13,  pp.  915-916,  1901. 
Describes  its  occurrence  and  its  bearing  on  the  stratigraphy  of  the  Mississippi  Valley. 
12.  Zone  of  maximum  richness  in  ore  bodies. 
Science,  new  ser.,  vol.  14,  pp.  577-578,  1901. 
Contains  abstracts  of  recent  papers  by  Emmons  and  Weed. 
L3.  Horizons  of  Arkansas  and  Indian  Territory  coals  compared  with  those  of  other 
trans-Mississippian  coals. 
Eng.  &  Mg.  Jour.,  vol.  71,  pp.  692-693,  2  figs.,  1901. 
Discusses  the  relations  of  the  coal-bearing  horizons  of  the  trans-Mississippian  region. 
14.  The  stratigraphical  location  of  named  trans-Mississippian  coals. 
Eng.  &  Mg.  Jour.,  vol.  72,  p.  198,  1901. 
Gives  list  of  geological  formations  and  the  coals  occurring  in  each. 
15.  Contiguity  of  ore  deposits  of  different  generic  relationships. 
Abstract:  Eng.  &  Mg.  Jour.,  vol.  72,  pp.  597-598,  1901. 
16.  Diverse  origins  and  diverse  times  of  formation  of  the  lead  and  zinc  deposits  of 
the  Mississippi  Valley. 
Mining  &  Metallurgy,  vol.  24,  pp.  715-717.  1901. 
17.  ( )rigine  eolienne  du  loess. 
Soc.  Beige  de  Geol.,  de  Paleont.  et  d'Hydrol.,  Bull.,  vol.  12,  pp.  14-21.  1901. 
Discusses  the  origin  of  the  loess  of  the  Mississippi  Valley. 
