peop.  j.  w,  judd  ox  ixcxrsioxs  or  teetiaet 
May  1S93. 
As  lone:  ago  as  1S59  Mitscherlich  brought  forward  the  results  of  his 
studies  of  the  rock-fragments  entangled  in  the  lavas  of  the  Eifei. 
though  his  memoir  was  not  published  in  full  till  1865.1 
Between  the  vears  1862  and  1865  an  animated  controversy  wu> 
carried  on  with  respect  to  some  of  the  very  highly-altered  materials 
found  enclosed  in  igneous  rocks  of  the  Kaiserstuhl  by  EL  Biscner. 
von  Hochstetter,  and  Xenngott : 2  and  in  lbSO  .John  Arthur  Phillip? 
very  tullv  discussed  the  points  of  distinction  between  greatly  altered 
and*  recrystallized  foreign  inclusions  and  the  remarkable  segregation- 
nodules  found  in  many  granites. 
We  are  indebted  to  J.  Lehmann  for  a  very  interesting  memoir^ 
published  in  1874.  in  which  he  fully  described  the  alteration  of 
the  several  minerals  in  the  various  aqueous  and  igneous  rocks  found 
among  the  ejected  materials,  or  enclosed  in  the  lavas,  of  the  Eifel 
volcanoes  :  4  a  subject  which  had.  as  we  have  seen,  earlier  engaged 
the  attention  of  Mitscherlich.  In  1880,  L.  Van  W erveke  returned  to 
the  discussion  of  the  foreign  fragments  enclosed  in  the  igneous  masses 
of  the  Kaiserstuhl,  and  described  a  clear  case  of  gneiss  caught  up  in 
nepheliniie.  In  1^-84,  E.  von  Sandoerger  gave  an  account  of  frag¬ 
ments  of  rock  caught  up  in  the  basalt  of  V aurod  :  in  the  following 
vear  von  C hr ustschoff  described  the  enclosures  01  granite  in  the 
basalt  of  Striegau.7  while  still  more  recently,  in  1890.  A.  Lacroix  has 
given  a  very  full  and  interesting  account  of  fragments  of  foreign 
igneous  rocks  contained  in  the  lavas  of  Auvergne.'  In  the  same 
year  there  appeared  the  valuable  memoir  of  H.  Backstrom  on  the 
inclusions  of  augite-granite  and  other  rocks  in  basic  eruptive?  in 
Scandinavia.9  Within  the  last  year  (1892),  Er.  Graeff  has  again 
taken  up  the  discussion  of  the  included  masses  in  the  Kaiserstuhl 
eruptives.'  . 
A  series  of  phenomena  somewhat  similar  to  those  round .  in 
natural  lavas  were  described  by  E.  Hussak,  in  1880,  as  resulting 
from  the  fusion  of  basalt  and  the  enveloping  of  pieces  of  granite  by 
1  E.  Mitscherlich.  *  TTeber  die  vulkanisehen  Eracheinnngen  in  der  Eifel,  and 
iiber  die  Metamorokie  der  Gesteine  durck  erhokte  Temperatur,  Abhandl.  d. 
konieL  Akad.  d.  Wissensch.  Berlin  (Phys.  .  1865,  pp.  1-68-  ... 
2  See  Terh.  Aaturf.  GeseEsck  Freib.-i.-B.  vol.  li.  p.  40i .  yoL  m.  jh.  p.  1. 
pts.  3  A  4,  p.  165.  and  also  Verb.  d.  k.  k.  geol.  Eeichsanst.  1865,  pp.  0-1.. 
t  3  .  on  Concretionary  Patches  and  Eragments  of  other  Eccss  contained  m 
Granite.’ Quart.  Jourd.  Geol.  Soc.  vol.  vswi.  (1880  pp.  1-22. 
4  •  Entersuehunsen  iiber  die  Einwirkung  ernes  feung-flussigen  basaltischen 
Magmas  auf  Gesteins-  und  M ineral-Einsehlnase,  angesteht  an  Baven  und 
Basalten  des  Ahederrheins/  Verb,  des  Aaturh.  Vereins  der  preuss.  Eheml.  u. 
Westf.  1874.  pp.  1-40.  .  T-  .  .  , ,  . 
3  ‘  Gneiss-Enaschlnsae  aus  Nephelinit  von  Oberbergen  am  Kaiserstuhl, 
Veues  Jabrb.  1880,  voL  ii.  p.  283.  .  ,  ,,  , 
6  •  Xeue  Einscklusse  im  Basalt  von  A  aurod  bei  Wiesbaden.  Terhandi.  d. 
k.  k.  geol.  Eeicbsanst.  1884,  p.  1  < .  .  ,,  ...  , 
-  •  Mikropetrograpbische  Mittheilungen,  Tschermak  s  Mineral,  u.  Peirogr. 
Mittb.  vol.  vii.  (1885)  p.  295.  .  , .  :  t?  n 
-  <  Sur  les  Enclaves  Acides  des  Roches  Volcaniques  de  1  Auvergne,  BuL.  d<- 
Serv.  de  la  Carte  Geol.  de  France,  Ao.  11  (vol.  ii). 
3  ■  Eeber  fremde  Gesteinseinscbliisse  in  einigen  Skandinawseben  Diabasen. 
Bibans;  till  Svenska  Yetensk.-Akad.  Handlingar.  vol.  wi.  pp.  1-38. 
10  Afitth.  der  Grossherzogl.  Badiseben  Geol.  Eandesanst.  vol.  xly.  p.  4Uo. 
