Farming  of  Gloucestershire . 
125 
on  the  Severn,  the  red  marls  are  121  feet  thick  ; they  rest  on  the  upturned 
carboniferous  limestone,  and  are  covered  by  the  lias. 
At  Westbury-on-Severn  the  marls  are  357  feet  thick.  These  marls  are 
often  variegated  with  blue  and  red  tints,  the  blue  increasing  towards  the 
surface,  ami  in  the  fissures  where  water  descends  ; the  blue  colour  is  attri- 
buted to  the  de-oxidating  influence  of  vegetable  matter  in  the  marls,  as 
the  old  red-sandstone,  where  the  deep  red  peroxide  of  iron  is  often  con- 
verted into  a proto-salt,  giving  the  marl  a greenish  or  bluish  colour. 
In  composition  these  marls  are  very  complicated,  and  hence  the  fertility 
of  the  district  and  the  peculiarities  of  the  mineral  waters  at  Cheltenham 
and  elsewhere,  which  rise  up  from  them,  dissolving  out  the  salts  and  form- 
ing new  combinations  in  their  progress.  These  waters  contain  sea-salt 
and  the  sulphate  of  soda  and  magnesia,  and  sometimes  also  sulphate  of 
lime,  oxide  of  iron,  chloride  of  magnesia,  iodine  and  bromine.* 
The  composition  of  the  red  marl  of  Aust  Cliff  is  given 
by 
Sir  Henry 
elabeche : — 
Silica  . ■ 
. 48-69 
Potash 
3-15 
Protoxide  of  iron 
. 4-79 
Phosphoric  acid 
trace 
Peroxide  of  iron 
. 9-09 
Sulphuric  acid  . 
0-27 
Alumina  . 
8-77 
Chlorine  . 
trace 
Lime  . . 
8-6S 
Carbonic  acid  . 
8-56 
Magnesia  . . 
. 0-94 
Organic  matter  . 
1-18 
Soda 
. 0-53 
Water  and  loss  . 
4-25 
North  of  Newent  the  red-sandstone  division  emerges  from  beneath  the 
marls,  and  begins  to  occupy  a wide  space  parallel  with  the  Malverns. 
With  the  sandstone  are  beds  of  conglomerate  full  of  rounded  pebbles  of 
the  older  rocks,  especially  the  quartzose  rock  of  Bromsgrove.  These  sands, 
often  in  beds,  are  sometimes  quite  loose,  and  easily  blown  by  the  winds,  so 
that  not  even  gorse  or  larch  will  grow  on  them  ; whilst  the  conglomerates 
are  mere  gravel  beds,  the  pebbles  of  which  are  used  for  mending  roads. 
8.  Lias. 
9.  Inferior  oolite. 
10.  Fuller's  earth. 
11.  Great  oolite. 
12.  Forest  marble. 
13.  Cornhrash. 
14.  Oxford  clay." 
These  latter  geological  strata  being  those  on  which  the  principal 
farming  of  the  county  is  carried  on,  I have  given  a description  of 
the  soils  in  the  articles  on  the  farming  of  the  Vale  of  the  Thames 
and  the  Cotswolds,  and  the  farming  of  the  “ Vale,”  thinking  it 
desirable  not  to  further  burden  this  Report  with  a scientific 
description. 
Agricultural  Botany  of  the  County. — Certain  groups  of  our 
native  plants  are  well  known  to  afford  valuable  indications  of  the 
barrenness  or  fertility,  and  also  of  the  quality  of  soils,  since,  like 
the  cultivated  crops,  they  require  an  abundant  supply  of  particular 
mineral  substances,  and  will  not  flourish  where  these  are  absent 
from  the  ground.  A practised  eye  will  often  detect  changes  in 
the  character  of  the  natural  herbage,  where  there  is  no  apparent 
difference  of  physical  condition,  and  those  changes  point  out 
an  alteration  in  the  soil.  To  give  their  full  value  to  such  indica- 
* See  Murchison's  ‘Geology  of  Cheltenham.’ 
