﻿ARTICLE 
  XIV. 
  

  

  Contributions 
  to 
  the 
  Geology 
  of 
  the 
  Tertiary 
  Formations 
  of 
  Virgi- 
  

   nia. 
  By 
  William 
  B. 
  Rogers, 
  Professor 
  of 
  Natural 
  Philosophy 
  in 
  the 
  

   University 
  of 
  Virginia, 
  and 
  Henry 
  D. 
  Rogers, 
  Professor 
  of 
  Geology 
  in 
  

   the 
  University 
  of 
  Pennsylvania. 
  Read 
  May 
  5th, 
  1835. 
  

  

  I. 
  GEOLOGY 
  OF 
  A 
  PORTION 
  OF 
  THE 
  PENINSULA 
  BETWEEN 
  THE 
  

  

  JAMES 
  AND 
  YORK 
  RIVERS. 
  

  

  1. 
  The 
  region 
  of 
  which 
  we 
  are 
  about 
  to 
  treat, 
  comprises 
  the 
  coun- 
  

   ties 
  of 
  Elizabeth 
  City, 
  Warwick, 
  York 
  and 
  James 
  City, 
  and 
  the 
  lower 
  

   extremities 
  of 
  New 
  Kent 
  and 
  Charles 
  City 
  counties. 
  Its 
  length 
  in 
  a 
  

   north 
  west 
  direction 
  is 
  about 
  fifty, 
  and 
  its 
  mean 
  breadth 
  about 
  fourteen 
  

   miles. 
  In 
  Elizabeth 
  City 
  and 
  Warwick 
  counties, 
  and 
  the 
  eastern 
  

   portion 
  of 
  York 
  county, 
  the 
  general 
  level 
  of 
  the 
  surface 
  is 
  but 
  little 
  

   elevated 
  above 
  tide. 
  The 
  country 
  is 
  a 
  uniform 
  flat, 
  in 
  some 
  places 
  

   subject 
  to 
  be 
  occasionally 
  overflowed. 
  The 
  rest 
  of 
  the 
  region 
  in 
  ques- 
  

   tion 
  has 
  an 
  elevation 
  above 
  tide, 
  varying 
  from 
  twenty 
  to 
  eighty 
  feet. 
  

   But 
  few 
  points, 
  however, 
  in 
  the 
  district 
  have 
  a 
  level 
  corresponding 
  to 
  

   either 
  of 
  these 
  extremes, 
  and 
  by 
  far 
  the 
  larger 
  portion 
  of 
  the 
  surface 
  

   preserves 
  a 
  height 
  of 
  from 
  forty 
  to 
  fifty 
  feet. 
  

  

  2. 
  The 
  surface 
  of 
  this 
  more 
  elevated 
  portion, 
  though 
  preserving 
  a 
  

   general 
  level 
  of 
  remarkable 
  uniformity, 
  is 
  deeply 
  channelled 
  by 
  in- 
  

   numerable 
  ravines. 
  The 
  smaller 
  of 
  these 
  connect 
  themselves 
  with 
  

   large 
  ones, 
  and 
  these 
  with 
  the 
  wider 
  and 
  deeper 
  excavations 
  forming 
  

  

  