﻿360 
  JOURNAI, 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  15 
  

  

  Most 
  of 
  the 
  Lower 
  Cambrian 
  arenaceous 
  series 
  is 
  well 
  exposed 
  in 
  

   the 
  gorge 
  of 
  the 
  Susquehanna 
  River 
  through 
  the 
  Hellam-Chickies 
  

   Hills. 
  The 
  quartzite 
  at 
  Chickies 
  Rock 
  has 
  been 
  called 
  Chickies 
  quartz- 
  

   ite 
  since 
  1878, 
  when 
  the 
  name 
  was 
  first 
  used 
  by 
  Lesley 
  and 
  Frazer; 
  

   they 
  also 
  used 
  Hellam 
  quartzite 
  for 
  the 
  same 
  rocks 
  in 
  Hellam 
  Hills. 
  

   Lesley 
  and 
  Frazer 
  applied 
  the 
  name 
  Chickies 
  (Chickis) 
  to 
  the 
  quartz- 
  

   ite 
  and 
  associated 
  "quartz 
  slate" 
  but 
  not 
  to 
  the 
  overlying 
  phyllite, 
  

   and 
  later 
  Walcott 
  followed 
  the 
  same 
  usage, 
  applying 
  the 
  name 
  Chickies 
  

   to 
  the 
  quartzite. 
  Conglomerate 
  at 
  the 
  base 
  of 
  the 
  arenaceous 
  series 
  

   was 
  not 
  mentioned 
  by 
  these 
  early 
  writers 
  and 
  apparently 
  was 
  not 
  seen 
  

   by 
  them, 
  as 
  it 
  is 
  not 
  exposed 
  at 
  Chickies 
  Rock. 
  It 
  is 
  brought 
  to 
  the 
  

   surface 
  three 
  miles 
  to 
  the 
  west 
  in 
  the 
  midst 
  of 
  the 
  Hellam 
  Hills, 
  where 
  

   the 
  anticline 
  rises 
  higher, 
  and 
  is 
  there 
  included 
  in 
  what 
  was 
  later 
  

   called 
  by 
  Lesley 
  Chickies 
  quartzite. 
  These 
  basal 
  conglomeratic 
  

   beds, 
  to 
  which 
  the 
  name 
  Hellam 
  conglomerate 
  member 
  is 
  here 
  applied, 
  

   correspond 
  in 
  general 
  with 
  the 
  Weverton 
  and 
  Loudoun 
  formations 
  

   of 
  South 
  Mountain. 
  The 
  Hellam 
  conglomerate 
  member 
  lies 
  on 
  

   epidotic 
  amphibolite 
  schist 
  or 
  greenstone 
  and 
  aporhyolite, 
  which 
  

   are 
  altered 
  volcanic 
  rocks 
  related 
  to 
  the 
  pre-Cambrian 
  metabasalt 
  

   or 
  Catoctin 
  schist 
  and 
  aporhyolite 
  of 
  South 
  Mountain. 
  The 
  basal 
  

   beds 
  of 
  the 
  conglomerate 
  here 
  are 
  chlorite 
  schist 
  which 
  contains 
  glassy 
  

   quartz 
  grains 
  and 
  flat 
  fragments 
  of 
  chloritic 
  and 
  rhyolitic 
  schists, 
  

  

  