﻿Yerrill 
  — 
  Notes 
  on 
  the 
  Geology 
  of 
  the 
  Bermudas. 
  329 
  

  

  stantly 
  carried 
  away 
  by 
  waves 
  and 
  currents 
  into 
  deep 
  water. 
  

   Mosley 
  was, 
  I 
  think, 
  the 
  first 
  writer 
  who 
  stated 
  that 
  the 
  sand 
  

   is 
  chiefly 
  composed 
  of 
  shells* 
  and 
  that 
  the 
  same 
  is 
  true 
  of 
  the 
  

   limestones. 
  

  

  Figure 
  7. 
  — 
  Cliffs 
  of 
  asolian 
  limestone 
  on 
  the 
  North 
  shore, 
  showing 
  two 
  

   strongly 
  marked 
  planes 
  of 
  erosion, 
  the 
  npper 
  one 
  several 
  feet 
  above 
  high-tide 
  

   level. 
  The 
  honeycombed 
  rocks 
  are 
  hardened 
  by 
  infiltrations 
  and 
  coatings 
  of 
  

   calcite. 
  

  

  Our 
  party 
  dredged 
  up 
  large 
  quantities 
  of 
  the 
  sand 
  and 
  mud 
  

   in 
  various 
  depths 
  in 
  Harrington 
  Sound 
  ; 
  Castle 
  Harbor 
  ; 
  Mur- 
  

   ray 
  Anchorage, 
  Bailey 
  Bay 
  ; 
  and 
  in 
  the 
  main 
  Ship 
  Channel, 
  

   down 
  to 
  depths 
  of 
  50 
  feet 
  or 
  more. 
  A 
  large 
  amount 
  was 
  

   brought 
  back 
  for 
  careful 
  study. 
  

  

  All 
  these 
  samples, 
  whether 
  coarse 
  or 
  fine, 
  consist 
  mainly 
  of 
  

   molluscan 
  shells, 
  mostly 
  of 
  small 
  species, 
  and 
  badly 
  broken 
  up, 
  

   especially 
  in 
  the 
  finer 
  varieties 
  (fig. 
  8). 
  

  

  More 
  than 
  50 
  species 
  of 
  small 
  shells, 
  in 
  fresh 
  condition, 
  have 
  

   been 
  picked 
  out 
  from 
  a 
  small 
  part 
  of 
  this 
  material. 
  The 
  most 
  

   abundant 
  species 
  are 
  small 
  bivalves 
  of 
  many 
  kinds, 
  but 
  small 
  

   gastropods, 
  such 
  as 
  Cerithium, 
  Turbonilla, 
  Caecum, 
  and 
  Bis- 
  

   soidre 
  are 
  also 
  abundant, 
  and 
  of 
  many 
  species, 
  as 
  well 
  as 
  various 
  

   larger 
  forms 
  in 
  the 
  coarser 
  samples 
  (fig. 
  9). 
  With 
  the 
  shells 
  

   are 
  a 
  number 
  of 
  species 
  of 
  Foraminifera, 
  but 
  these 
  are 
  not 
  

   abundant. 
  There 
  are 
  also, 
  in 
  the 
  coarser 
  samples, 
  a 
  very 
  few 
  

   bits 
  of 
  broken 
  branched 
  corals 
  (chiefly 
  Millepora), 
  and 
  a 
  few 
  

   fragments 
  of 
  calcareous 
  algse, 
  sea-urchins, 
  bryozoans, 
  etc., 
  

  

  * 
  Notes 
  by 
  a 
  Naturalist 
  on 
  the 
  Challenger, 
  p. 
  19, 
  1879. 
  

  

  Am. 
  Jour. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  IX, 
  No. 
  53.— 
  May, 
  1900. 
  

   23 
  

  

  