Volcanos  on  the  Banks  of  the  Rhine.  5 
tal  direction,  but  fome  are  perpendicular,  and  others  in- 
clining towards  the  Rhine,  which,  being  very  low, 
fhews  many  of  them  in  the  bed  of  the  river  itfelf;  they 
rife  from  thence  into  the  mountain  (where  is  the  prefent 
quarry)  above  100  feet.  They  are,  as  I mentioned  be- 
fore, chiefly  pentagonal;  the  fmalleft  are  in  general  the 
moft  diftindt  and  regular,  about  fix  inches  diameter;  the 
largeft  of  the  columns  that  I meafured.in  this  quarry  (or. 
indeed  that  I had  remarked  any  where)  was  about  three 
feet  long,  and  about  one  foot  and  a half  diameter.  The. 
other  lavas  in  this  neighbourhood  are  of  the  fame  fub- 
ftance,  and  fome  incline  to  the  fame  forms,  but  none  fo 
regular.  I have  not  the  leaft  doubt  but  that  all  bafaltes, 
wherefoever  they  exift,  have  originated  from  fubterra- 
neous  fire,  and  are  true  lavas.. 
I hope  fome  one,  who  has  more  leifure,  will  examine 
this  curious  country  particularly.  It  is  wondeful  to  me, 
that  fuch  vifible  tokens  of  great  volcanic  productions,  in 
a country  fo  well  inhabited,  fhould  not  have  attracted  the 
attention  of  naturalifts  more  than  they  feem  to  have 
done. 
I muft  not  forget  to  mention  another  curious  circum- 
ftance  : at  Andernach,  between  Bonn  and  Coblenz,  I faw 
vaft  heaps  of  tuffa  ready  cut,  lying  on  the  banks  of 
the  Rhine,  and  fome  Dutch  veflels  loading  it;  upon 
enquiry 
