RECENT    WORK    ON    NEW    ENGLAND    GRANITES.  357 
the  results  of  such  scientific  observations  as  were  made  in  the  course  of 
the  work.  In  order  to  accomplish  these  various  purposes  it  has  been 
divided  into  two  parts — a  scientific  and  an  economic  part.  The  first 
is  practically  a  brief  text-book  on  granite  in  general,  illustrated  by  the 
i  granite  quarries  of  Maine  and  written  as  far  as  has  been  possible  in 
untechnical  language,  so  as  to  be  intelligible  to  working  and  business 
men.  This  part  treats  of  the  origin,  mineralogical  and  chemical  com- 
position, texture,  structure,  physical  properties,  and  classification  of 
granite  and  "black  granites."  Under  the  heading  "Structure"  the 
[nature  and  origin  of  sheets,  rift,  grain,  flow  structure,  joints,  headings, 
and  faults  are  considered.  Dikes,  veins,  "knots"  (segregations),  geodes, 
inclusions,  and  contacts  are  described  and  discussed,  as  well  as  the  dis- 
coloration and  decomposition  of  granite. 
In  the  economic  part  the  various  tests  of  granite,  the  adaptation  of 
the  stone  to  different  uses,  and  the  methods  of  granite  quarrying  are 
first  considered.  An  economic  classification  of  Maine  granites  based 
upon  visual  characteristics  is  next  given,  and  next  follow  the  descrip- 
tions of  the  quarries  and  their  products,  the  matter  here  being  arranged 
by  counties  in  alphabetic  order.  These  descriptions  follow  a  uniform 
method,  taking  up,  in  succession,  (1)  the  name  and  location  of  quarry, 
name  and  address  of  operator  and  superintendent;  (2)  the  granite, 
including  its  description  in  the  rough  and  under  the  microscope, 
together  with  the  results  of  any  tests  and  analyses;  (3)  the  quarry, 
its  dimensions,  drainage,  and  water  supply;  (4)  the  stripping  and  rock 
structure ;  (5)  the  plant,  including  an  enumeration  of  all  machines  and 
pneumatic  tools,  to  show  its  capacity;  (6)  the  means  of  transportation; 
(7)  labor,  both  of  men  and  animals;  (8)  product,  its  uses  and  market, 
together  with  the  names  and  location  of  a  few  buildings  or  monuments 
in  whose  construction  the  stone  has  been  used. 
At  the  end  of  the  report  is  a  bibliography  on  the  economic  geolog}r 
of  granite  and  a  glossary  of  such  scientific  terms  as  were  unavoida- 
bly used  and  also  of  current  quarry  terms.  The  report  includes  14 
plates  illustrating  various  features  of  scientific  or  economic  interest 
in  the  quarries  or  their  product  and  39  text  figures.  Most  of  these 
text  figures  are  diagrams  showing  the  course  of  joints,  headings,  and 
dikes  at  the  quarries,  but  others  illustrate  "rift,"  sheet  structure, 
"sap,"  or  the  use  of  explosives,  or  show  the  location  of  individual 
quarries  at  the  industrial  centers.  The  situation  of  these  centers  is 
indicated  by  symbols  on  the  geological  map. 
WORK  IN  OTHER  STATES. 
A  report  on  the  granite  quarries  of  New  Hampshire,  Massachu- 
setts, and  Rhode  Island  will  follow  the  plan  of  the  economic  part  of 
that  on  Maine  granites,  but  will  include  such  supplementary  matter 
of  scientific  interest  as  has  been  collected  in  the  course  of  the  work. 
