FOR    THE    YEARS   1901-1905,   INCLUSIVE.  255 
Ogilvie  (Ida  H.) — Continued. 
5.  The  high  altitude  conoplain;  a  topographic  form  illustrated  in  the  Ortiz  Mountains 
[New  Mexico]. 
Am.  Geol.,  vol.  36,  pp.  27-34, 1  pi.,  1905. 
Discusses  the  conditions  of  rainfall  and  erosion  by  which  the  conoplain  is  produced. 
6.  Geology  of  the  Paradox  Lake  quadrangle,  New  York. 
N.  Y.  State  Mus.,  Bull.  96,  pp.  461-508,  17  pis.,  3  tigs.,  and  map,  1905. 
Describes  the  general  geology,  the  character  and  occurrence  of  Cambrian  strata,  and  in  detail 
the  physiography,  glaciology,  and  petrography  of  the  area. 
O'Harra  (Cleophas  C. ). 
1.  Black  Hills  ore  deposits. 
Int.  Mg.  Cong.,  4th  session,  pp.  97-100,  1901. 
Describes  the  occurrence  of  the  gold  ores. 
2.  The  mineral  wealth  of  the  Black  Hills  [South  Dakota]. 
S.  Dak.  Geol.  Surv.,  Bull.  no.  3, 136  pp.,  31  pis.,  1902;  S.  Dak.  School  of  Mines,  Bull.  no.  6,  Dept 
of  Geol.,  pp.  1-88,  22  pis.,  1902. 
Gives  a  general  geological  sketch  cf  the  geology  of  the  Black  Hills  and  describes  the  occur- 
rence of  the  minerals. 
3.  The  geology  and  mineralogy  of  the  Black  Hills  region. 
Black  Hills,  South  Dakota.  Papers  read  before  the  Black  Hills  Mining  Men's  Assoc,  pp.  119- 
127,  1904.    Am.  Mg.  Cong.,  6th  Ann.  Sess.,  Rept.  of  Proc,  pp.  87-93,  1904. 
Describes  the  general  topographic  and  geologic  features  and  character  of  the  rocks  of  the 
region,  and  gives  notes  upon  the  occurrence,  character,  and  geologic  relations  of  the  ore 
deposits,  chiefly  gold  ores. 
O'Harra  (C.  C),  Darton  (N.  H.)  and. 
1.  Aladdin  folio,  Wyoming-South  Dokota-Montana. 
See  Darton  (N.  H.)  and  O'Harra  (C.  C),  1. 
Ohly  (J.). 
1.  The  origin  of  petroleum.     Different  theories  which  have  been  advanced  and  the 
circumstances  for  and  against  them. 
Mines  &  Minerals,  vol.  22,  pp.  532-533,  1902. 
Oliphant  (F.  H.). 
1.  [In  discussion  of  paper  by  R.  Pearson  on  "  The  discovery  of  natural  gas  in  Sussex, 
Heathfield  district."] 
Inst.  Mg.  Engrs.  [Engl.],  Trans.,  vol.  26,  pp.  505-506  [1904]. 
A  short  note  in  regard  to  the  distribution  of  natural  gas  in  the  United  States. 
2.  Petroleum. 
U.  S.  Geol.  Surv.,  Min.  Res.  of  U.  S.  for  1903,  pp.  635-718,  1904. 
Includes  a  table  showing  the  stratigraphic  position  of  petroleum-producing  horizons  in  the 
Appalachian  and  Lima-Indiana  iields. 
Olsson-Seffer  (Pehr). 
1.  Examination  of  organic  remains  in  post-Glacial  deposits. 
Am.  Nat.,  vol.  37,  pp.  785-797,  2  figs.,  1903. 
Discusses  methods  of  collecting  and  examining  plant  remains  from  Quaternary  deposits, 
particularly  from  peat-bogs. 
Ordonez  (Ezequiel). 
1.  Las  rhyolitas  de  Mexico. 
Mexico  Inst,  Geol.,  Bui.  no.  14,  75  pp.,  5  pis.,  1900;  no.  15,  76  pp.,  11  pis.,  1901. 
Describes  the  macroscopic  and  microscopic  characters  of  the  rhyolites  and  their  distribution. 
2.  La  industria  minera  en  Mexico. 
Ciencia  y  Arte,  Mexico,  1901,  19  pp.     (Not  seen.) 
3.  The  mining  district  of  Pachuca,  Mexico. 
Eng.  and  Mg.  Jour.,  vol.  72,  pp.  719-721,  1901. 
Contains  notes  on  the  geology  and  mineralization  of  the  region. 
4.  The  onyx-marble  deposits  of  Jimulco,  Coahuila'  [Mexico]. 
Soc.  Cient.  Ant.  Alz.,  Mem.,  vol.  15,  pp.  381-385,  1901. 
