118 
MAKLS  AND  CLAYS  OF  THE  MALTESE  ISLANDS.  [Feb.  1893, 
I  dow  append  a  chronological  list  of  the  published  notices  and 
memoirs  having  reference  to  this  subject : — 
1843. 
1860. 
1864. 
1866. 
1870. 
1874. 
1876. 
1879. 
1890. 
1891. 
1891. 
Spratt,  T.  ‘  On  the  Geology  of  the  Maltese  Islands.’  Proc.  Geol. 
Soc.  vol.  iv.  p.  225. 
Gulia,  G.  ‘  Geologist’  (Notes  and  Queries)  for  1860,  p.  421 
Adams,  A.  L.  ‘  Outline  of  the  Geology  of  the  Maltese  Islands.' 
Ann.’ &  Mag.  Nat.  Hist.  ser.  3,  vol.  xiv  p  1 
Hutton,  F.  W.  ‘  Sketch  of  the  Physical  Geology  of  the  Island  ot 
Malta.’  Geol.  Mag.  for  1866,  p.  146.  , 
Adams,  A.  L.  *  Notes  of  a  Naturalist  m  the  Nile  Valley  and  Malta. 
Edinburgh. 
Fuchs,  Th.  ‘  Has  Alter  der  Tertiarschichten  von  Malta.’  Sitzungsber. 
d.  k.  k.  Akad.  der  Wissensch.  Wien,  vol.  lxx.  p.  92.  ) 
Fuchs,  Th.  ‘  Ueher  den  sogenannten  Badner  Tegel  auf  Malta. 
Sitzungsber.  d.  k.  k.  Akad.  d.  Wissensch.  Wien,  vol.  lxxiii.  p.  67. 
Adams,  A.  L.  ‘  On  Remains  of  Mastodon  and  other  Vertebrata  of 
the  Miocene  Beds  of  the  Maltese  Islands.’  Quart.  Journ.  Geol. 
Soc.  vol.  xxxv.  pp.  517-530. 
Murray,  John.  ‘  The  Maltese  Islands,  with  special  reference  to  their 
Geological  Structure.’  Scot.  Geogr.  Mag.  vol.  vi.  p.  449. 
Cooke,  J.  H.  ‘  Notes  on  the  Pleistocene  Beds  of  Gozo.’  Geol.  Mag. 
for’ 1891,  p.  348.  ,  . 
Gregory,  J.  W.  ‘  The  Maltese  Fossil  Echinoidea  and  their  Evidence 
on  the  Correlation  of  the  Maltese  Rocks.’  Trans.  Roy.  Soc.  Edin. 
vol.  xxxvi.  p.  585. 
II.  Physical  Features  and  General  Distribution 
oe  the  Strata. 
The  Maltese  Marls  and  Clays  occupy  the  third  place  both  in  the 
ascending  and  in  the  descending  order  of  the  Mnltese  formations. 
The  table  facing  this  page  shows  the  order  in  which  the  beds 
occur,  as  well  as  the  relation  that  they  bear  to  the  continental 
deposits. 
The  formation  known  as  the  ‘  Clays  ’  consists  of  marls  and  clays 
varying  considerably  in  their  lithological  characters  as  well  as  in 
their  distribution.  It  lies  conformably  between  th q  Globigerina- 
limestone  and  a  greensand  formation,  but  so  obscure  is  the  line  of 
demarcation  between  it  and  the  Gk)5f^6r7/icf-limestone,  and  so1 
striking  are  the  resemblances  of  the  fossil  fauna  of  each,  that  we 
seem  to  be  justified  in  considering  the  Clay  as  being  merely  an 
argillaceous  division  of  the  formation  upon  which  it  rests. 
In  Malta  the  formation  is  developed  only  in  the  northern  and 
north-western  districts,  where  it  extends  over  about  one  third  of 
the  total  area  of  the  island.  But  in  Gozo,  where  the  forces  of  denu¬ 
dation  have  been  more  actively  at  work,  it  is  so  scattered  among 
the  hills  and  plateaux  that  its  aggregated  area  would  not  amount 
to  more  than  one  fourth  of  that  of  the  island  in  which  it  occurs 
(see  fig.  1,  p.  120). 
In  common  with  all  the  beds  of  the  Maltese  group  this  formation 
has  been,  then,  extensively  denuded.  The  remnants  of  the  Clays 
that  occur  in  the  Dueira  Valley,  in  Gozo,  and  in  the  caves,  fissures, 
gorges,  and  valleys  of  both  islands,  show  that  at  one  time  the 
formation  probably  extended  much  farther  than  it  does  at  present. 
