DESCRIPTION    OF    AUTHORITIES. 
GODDARD. 
These  determinations  are  by  level  from  preliminary  railroad  surveys 
made  by  the  Central  Pacific  Railroad  Company  of  California.  Like 
all  preliminary  work,  they  are  not  in  the  highest  degree  reliable. 
GUYOT. 
Nearly  all  the  elevations  given  under  this  authority  are  in  the 
Appalachian  region,  and  were  determined  by  barometer.  They  are  of 
the  highest  character  of  this  class  of  work.  Most  of  the  figures  have 
been  compiled  from  Professor  Guyot's  articles  in  the  American 
Journal  of  Science  and  Arts. 
HAYDEN,  DR.  F.  V. 
Under  this  authority  is  given  all  work  done  by  the  United  States 
Geological  and  Geographical  Survey  of  the  Territories.  All  deter- 
minations are  barometric  or  trigonometric  resting  on  barometric 
bases. 
IVES,  LIEUT.  J.  C. 
Report  of  Colorado  Exploring  Expedition  (Thirty-sixth  Congress, 
first  session,  Senate  document).     All  determinations  are  barometric. 
JENNEY,  PROF.  WILLIAM    P. 
These  heights  were  abstracted  from  the  Atlas  of  the  Black  Hills. 
All  determinations  are  barometric. 
JONES,  CAPT.  W.  A. 
Report  of  Expedition  to  Northwestern  Wyoming  and  the  Yellow- 
stone Park,  1873.     All  determinations  are  barometric. 
KING,  CLARENCE. 
This  reference  is  mainly  to  the  work  of  the  Geological  Exploration 
of  the  Fortieth  Parallel.  All  determinations  are  barometric  or 
depend  upon  barometric  bases. 
MASSACHUSETTS    TRIGONOMETRIC    SURVEY    (MASS.  TRIG.  SURVEY) . 
This  includes  altitudes  of  stations  determined  trigonometrically 
by  a  survey  under  the  charge  of  Mr.  Simeon  Borden. 
MEXICAN    BOUNDARY    SURVEY. 
The  altitudes  given  under  this  heading  were  determined  by 
barometer  by  the  first  survey  of  the  boundary. 
MINNESOTA     GEOLOGICAL     AND     NATURAL     HISTORY     SURVEY      (MINN. 
STATE    SURVEY). 
These  elevations  were,  in  the  main,  determined  by  aneroid. 
