﻿8 
  

  

  MUSSELS 
  OF 
  CENTRAL 
  AND 
  NORTHERN 
  MINNESOTA. 
  

  

  The 
  Falls 
  of 
  St. 
  Anthony 
  at 
  Minncapohs 
  have 
  formed 
  a 
  similar 
  

   barrier 
  in 
  the 
  Mississippi 
  River, 
  but 
  with 
  this 
  difference: 
  Some 
  fish 
  

   have 
  evidently 
  been 
  able 
  to 
  ascend 
  these 
  falls 
  while 
  others 
  could 
  not 
  

   accomplish 
  it. 
  Accordingly, 
  we 
  find 
  in 
  the 
  Mississippi 
  above 
  the 
  falls, 
  

   and 
  in 
  its 
  tributaries 
  an 
  abundance 
  of 
  mussels 
  belonging 
  to 
  the 
  

   Lampsilis 
  or 
  mucket 
  group, 
  plenty 
  of 
  Anodonta, 
  SympTiynota, 
  Stro- 
  

   phituSfSbud 
  the 
  like, 
  but 
  not 
  a 
  solitary 
  specimen 
  was 
  seen 
  of 
  the 
  great 
  

   Quadrula 
  or 
  pig-toe 
  group. 
  The 
  falls 
  have 
  manifestly 
  furnished 
  in 
  

   some 
  way 
  an 
  effective 
  barrier 
  to 
  the 
  distribution 
  of 
  these 
  mussels. 
  

   On 
  the 
  other 
  hand, 
  the 
  Minnesota 
  River 
  enters 
  the 
  Mississippi 
  some 
  

   distance 
  below 
  the 
  falls, 
  and 
  it 
  contains 
  as 
  many 
  pig-toes 
  as 
  muckets. 
  

  

  The 
  pig-toes 
  also 
  ascended 
  the 
  glacial 
  river 
  Warren 
  into 
  Lake 
  Agassiz, 
  

   and 
  we 
  find 
  them 
  to-day 
  in 
  the 
  Red 
  River 
  of 
  the 
  North. 
  They 
  also 
  

   ascended 
  the 
  St. 
  Croix 
  River, 
  and 
  in 
  the 
  St. 
  Croix 
  drainage 
  they 
  are 
  

   even 
  more 
  numerous 
  in 
  species 
  than 
  the 
  muckets. 
  

  

  For 
  convenience 
  we 
  may 
  divide 
  the 
  lakes 
  and 
  rivers 
  which 
  were 
  

   examined 
  into 
  five 
  groups, 
  and 
  designate 
  them, 
  respectively, 
  the 
  

   St. 
  Croix 
  group, 
  the 
  Minnesota 
  River 
  group, 
  the 
  Red 
  River 
  group, 
  

   the 
  Crow 
  Wing 
  group, 
  the 
  Mississippi 
  River 
  group, 
  and 
  the 
  isolated 
  

   lakes. 
  

  

  MUSSELS 
  OF 
  THE 
  ST. 
  CROIX 
  GROUP. 
  

  

  The 
  lakes 
  and 
  rivers 
  in 
  this 
  eastern 
  central 
  portion 
  of 
  Minnesota 
  

   have 
  been 
  populated 
  with 
  mussels 
  by 
  way 
  of 
  the 
  St. 
  Croix 
  River. 
  

   This 
  connection 
  was 
  established 
  after 
  the 
  melting 
  of 
  the 
  glacier 
  and 
  

   has 
  not 
  been 
  materially 
  changed 
  since 
  that 
  period. 
  

  

  Joining 
  the 
  Mississippi 
  some 
  distance 
  below 
  St. 
  Paul, 
  and 
  having 
  

   no 
  falls 
  or 
  other 
  natural 
  obstruction 
  in 
  its 
  own 
  course, 
  the 
  St. 
  Croix 
  

   River 
  has 
  afforded 
  a 
  constant 
  and 
  easy 
  passage 
  for 
  all 
  the 
  Mississippi 
  

   species 
  of 
  fish 
  and 
  mussels. 
  Hence 
  we 
  find 
  a 
  goodly 
  variety 
  of 
  both 
  

   in 
  the 
  lakes 
  and 
  rivers 
  belonging 
  to 
  the 
  St. 
  Croix 
  drainage. 
  The 
  

   following 
  table 
  gives 
  the 
  geographic 
  distribution 
  of 
  the 
  various 
  

   mussels 
  found 
  here 
  during 
  the 
  present 
  survey: 
  

  

  Distribution 
  of 
  Mussels 
  in 
  St. 
  Croix 
  Drainage. 
  

  

  