﻿156 
  REPORT 
  UNITED 
  STATES 
  GEOLOGICAL 
  SURVEY. 
  

  

  Trachyte 
  flanks 
  both 
  sides 
  of 
  the 
  river 
  above 
  the 
  gap, 
  stretching 
  down 
  

   in 
  long, 
  low 
  ridges 
  from 
  the 
  mountains. 
  South 
  of 
  Bristol 
  Head,* 
  station 
  

   27 
  is 
  located 
  on 
  an 
  isolated 
  hill, 
  at 
  an 
  elevation 
  of 
  9,278 
  feet. 
  Opposite 
  

   this 
  station 
  South 
  River 
  flows 
  into 
  the 
  Rio 
  Grande. 
  On 
  the 
  former 
  a 
  

   group 
  of 
  very 
  great 
  interest 
  was 
  discovered, 
  a 
  group 
  of 
  monuments. 
  

   For 
  about 
  3 
  miles 
  along 
  the 
  east 
  side 
  of 
  South 
  River, 
  hundreds 
  of 
  "mon- 
  

   uments" 
  occur, 
  imparting 
  to 
  the 
  wooded 
  slope 
  that 
  is 
  studded 
  with 
  them 
  

   a 
  weird 
  and 
  picturesque 
  appearance. 
  A 
  long 
  ridge 
  separates 
  this 
  stream 
  

   from 
  the 
  parallel 
  creek 
  east 
  of 
  it. 
  On 
  the 
  west 
  side 
  this 
  ridge 
  falls 
  off 
  

   perpendicularly, 
  with 
  narrow, 
  rocky 
  walls 
  leading 
  off 
  from 
  the 
  precipice 
  

   at 
  right 
  angles. 
  It 
  is 
  on 
  these 
  walls 
  and 
  in 
  the 
  interstices 
  between 
  them 
  

   that 
  the 
  curious 
  products 
  of 
  erosion 
  are 
  found. 
  Rising 
  from 
  a 
  massive 
  

   base, 
  the 
  spire-shaped 
  columns, 
  profusely 
  ornamented 
  by 
  accessory 
  tow- 
  

   erlets, 
  reach 
  a 
  height 
  of 
  400 
  feet. 
  Several 
  of 
  them 
  cluster 
  together 
  

   below, 
  and, 
  separating 
  as 
  they 
  increase 
  in 
  height, 
  form 
  groups 
  that 
  for 
  

   unique 
  appearance 
  will 
  scarcely 
  find 
  their 
  equal. 
  Dark 
  spruce 
  timber, 
  

   trees 
  of 
  great 
  size, 
  seem 
  but 
  like 
  dwarfs 
  by 
  the 
  side 
  of 
  these 
  mighty 
  

   columns. 
  The 
  entire 
  surface 
  of 
  the 
  walls 
  is 
  corrugated, 
  ornamented 
  

   with 
  diminutive 
  monuments, 
  while 
  the 
  edges 
  and 
  the 
  top 
  are 
  literally 
  

   covered 
  with 
  the 
  graceful 
  forms. 
  For 
  3 
  miles 
  in 
  length 
  and 
  about 
  half 
  

   a 
  mile 
  in 
  width 
  the 
  surface 
  is 
  covered 
  with 
  the 
  monuments. 
  Through 
  

   openings 
  in 
  the 
  timber 
  the 
  groups 
  appear, 
  like 
  so 
  many 
  statues 
  placed 
  

   there 
  by 
  the 
  skillful 
  hand 
  of 
  nature, 
  while 
  again 
  they 
  reach 
  far 
  above 
  

   the 
  tops 
  of 
  the 
  highest 
  trees. 
  Owing 
  to 
  the 
  comparative 
  regularity 
  of 
  

   the 
  arrangement 
  of 
  the 
  walls, 
  certain 
  zones 
  are 
  more 
  richly 
  supplied 
  

   with 
  the 
  monuments 
  than 
  others. 
  Looking 
  down 
  from 
  above 
  into 
  the 
  

   deep 
  chasms 
  between 
  the 
  walls, 
  the 
  slender 
  columns 
  capped 
  with 
  the 
  

   projecting 
  top, 
  occurring 
  of 
  all 
  possible 
  sizes, 
  present 
  a 
  view 
  at 
  once 
  

   impressive 
  as 
  a 
  whole 
  and 
  singularly 
  beautiful 
  in 
  detail. 
  Trachytio 
  

   conglomerate, 
  that 
  shows 
  indubitable 
  evidence 
  of 
  having 
  been 
  depos- 
  

   ited 
  by 
  water, 
  furnishes 
  the 
  material 
  for 
  the 
  formation 
  of 
  the 
  monuments. 
  

   On 
  average, 
  the 
  thickness 
  of 
  this 
  stratum, 
  that 
  also 
  occurs 
  at 
  numerous 
  

   other 
  localities, 
  is 
  about 
  600 
  feet. 
  In 
  consequence 
  of 
  erosion, 
  the 
  walls 
  

   jutting 
  out 
  from 
  the 
  precipice 
  do 
  not 
  show 
  the 
  entire 
  thickness 
  of 
  the 
  

   stratum, 
  but 
  are 
  only 
  about 
  500 
  feet 
  high. 
  Rising 
  from 
  the 
  very 
  base 
  

   of 
  the 
  walls, 
  the 
  highest 
  monuments 
  reach 
  about 
  400 
  feet, 
  but 
  the 
  average 
  

   height 
  may 
  be 
  quoted 
  at 
  about 
  60 
  to 
  80 
  feet. 
  The 
  conglomerate 
  is 
  com- 
  

   posed 
  of 
  large 
  and 
  small 
  trachytic 
  bowlders 
  that 
  are 
  but 
  loosely 
  cemented 
  

   by 
  volcanic 
  sand, 
  which 
  is 
  redeposited 
  by 
  water. 
  At 
  no 
  point 
  was 
  it 
  ob- 
  

   served 
  that 
  the 
  cementing 
  medium 
  produced 
  a 
  harder 
  rock 
  than 
  at 
  the 
  

   place 
  where 
  the 
  largest 
  number 
  of 
  monuments 
  are 
  found. 
  In 
  contradis- 
  

   tinction 
  to 
  the 
  formation 
  of 
  the 
  monuments 
  in 
  the 
  Garden 
  of 
  the 
  Gods, 
  

   those 
  of 
  this 
  locality 
  are 
  primarily 
  formed 
  almost 
  entirely 
  by 
  aqueous 
  

   erosion. 
  Numerous 
  observations, 
  showing 
  the 
  form 
  in 
  every 
  stage 
  of 
  

   development, 
  have 
  demonstrated 
  the 
  process 
  of 
  generation. 
  Assuming 
  

   before 
  us 
  the 
  vertical 
  or 
  nearly 
  vertical 
  wall 
  of 
  trachytic 
  conglomerate, 
  

   we 
  find 
  that 
  innumerable 
  large 
  and 
  small 
  bowlders 
  project 
  from 
  its 
  sur- 
  

   face. 
  Water 
  slowly 
  moving 
  down 
  along 
  the 
  wall 
  finds 
  a 
  temporary 
  rest- 
  

   ing 
  place 
  upon 
  reaching 
  one 
  of 
  these 
  bowlders, 
  and 
  then 
  flows 
  down 
  on 
  

   one 
  or 
  the 
  other, 
  or 
  both 
  sides 
  of 
  it. 
  Owing 
  to 
  the 
  very 
  readily 
  disin- 
  

   tegrating 
  character 
  of 
  the 
  conglomerate, 
  the 
  cementing 
  grains 
  of 
  sand 
  

   and 
  the 
  small 
  amount 
  of 
  clay 
  intermixed 
  are 
  readily 
  washed 
  away, 
  and 
  

   gradually 
  a 
  vertical 
  groove 
  appears 
  on 
  either 
  side 
  of 
  the 
  bowlder. 
  This 
  

   groove 
  is, 
  in 
  the 
  course 
  of 
  time, 
  worn 
  deeper 
  and 
  deeper, 
  the 
  bowlder 
  

  

  * 
  Comp. 
  Report 
  Uuited 
  States 
  Geological 
  Survey, 
  1874, 
  p. 
  199. 
  

  

  