182  BIBLIOGRAPHY    OF    NORTH    AMERICAN    GEOLOGY 
Irving-  (John  Duer) —  Continued. 
5.  Microscopic  structure  and  origin  of  certain  stylolitic  structures  in  limestone 
Abstract:  Am.  Geol.,  vol  33,  pp.  266-267,  1904;  Science,  new  ser.,  vol.  19,  p.  580,  1904. 
Discusses  the  character  and  origin  of  stylolites. 
6.  Ore  deposits  of  the  Ouray  district,  Colorado. 
U.  S.  Geol.  Surv.,  Bull.  no.  260,  pp.  50-77,  4  tigs.,  1905. 
Describes  the  general  geology,  and  the  occurrence,  relations,  and  economic  development  of 
gold  and  silver-bearing  deposits. 
7.  Ore  deposits  in  the  vicinity  of  Lake  City,  Colorado. 
U.  S.  Geol.  Surv.,  Bull.  no.  260,  pp.  78-84,  1905. 
Describes  the  general  geology,  and  the  occurrence,  character,  and  relations  of  the  gold  and 
silver-bearing  fissure  veins. 
8.  University  training  of  engineers  in  economic  geology. 
Econ.  Geol.,  vol.  1,  pp.  77-82,  1905. 
9.  The  ore  deposits  of  the  Ouray  quadrangle  [Colorado]. 
Abstract:  Science,  new  ser.,  vol.  21,  pp.  916-917,  1905. 
Irving'  (John  Duer)  and  Emmons  (S.  F. ). 
1.  Economic  resources  of  the  northern  Black  Hills.     Part  II.     Mining  geology. 
U.  S.  Geol.  Surv.,  Professional  Paper  no.  26,  pp.  43-222,  19  pis.,  11  figs.,  1904. 
Describes  the  character,  occurrence,  and  geologic  relations  of  the  gold,  silver,  copper,  tin 
and  tungsten  ores,  and  their  economic  development. 
Irving  (J.  D. )  and  Emmons  (YV.  H.).  ' 
1.   Economic  geology  of  the  Needle  Mountains  quadrangle  [Colorado]. 
('.  S.  Geol.  Surv.,  Geol.  Atlas  of  U.  S.,  folio  no.  131,  1905. 
Describes  the  character,  occurrence,  and  relations  of  the  gold  and  silver  ores. 
Ishikawa  (S. ). 
1.  Latest  eruption  of  Colima  volcano,  Mexico.     [In  Japanese.] 
Tokyo  Geol.  Soc,  .lour.,  vol.  11,  pp.  98-103,  L904. 
J. 
Jackson  (J.  F. ). 
1.  Copper  mining  in   Upper  Michigan,  a  description  of  the  region,  the  mines,  and 
some  of  the  methods  and  machinery  used. 
Mines  &  Minerals,  vol.  23,  pp.  535-540,  9  figs.,  1903. 
Contains  observations  on  the  occurrence  of  the  copper-ore  deposits. 
Jackson  (Robert  T. ). 
1.  Charles  Emerson  Beecher. 
Am.  Nat.,  vol.  38,  pp.  407-426,  1  pi.  (por.),  1904. 
Gives  an  account  of  his  life  and  work,  and  a  list  of  his  published  papers. 
Jacobs  (E. ). 
1.  Ore  quarrying  in  the  Boundary  district  of  British  Columbia. 
Eng.  Mag.,  vol.  26,  pp.  236-249,  illus.,  1903. 
Describes  briefly  the  occurrence  and  character  of  copper-ore  deposits. 
2.  The  coal  fields  of  Crow's  Nest  Pass,  British  Columbia. 
Eng.  Mag.,  vol.  27,  pp.  36-57,  illus.,  1904. 
Describes  the  location  of  the  field,  the  occurrence  of  the  coal,  and  the  mining  operations. 
Jaekel  (0.). 
1.  Bemerkungen  iiber  den  Beinbau  der  Trilobiten. 
Zeitsch.  d.  deutsch.  geol.  Gesell.,  Bd.  5-4,  pp.  53-55  (of  Brief.  Mitt),  1902. 
Discusses  criticisms  by  C.  E.  Beecher  of  a  paper  by  the  author  on  the  structure  of  trilobites. 
Jaggar  (Thomas  Augustus). 
1.  The  laccoliths  of  the  Black  Hills  [South  Dakota]. 
U.  S.  Geol.  Surv.,  21st  Ann.  Rept.,  pt.  3,  pp.  163-290,  24  pis.,  40  figs.,  1901. 
Describes  the  occurrence  of  the  sedimentary  and  igneous  rocks,  and  the  character,  occurrence, 
and  distribution  of  the  laccolithic  intrusives,  and  discusses  the  physiographic  form  of  eroded 
domes. 
