touTWELL.]     OIL    AND    ASPHALT    IN    SALT    LAKE    BASIN,    UTAH.  473 
it  a  depth  of  500  feet  beneath  the  present  snrfaee  have  been  deter- 
mined (April  15,  1904)  by  Dr.  W.  H.  Pall,  paleontologist  of  the 
Jnited  States  Geological  Survey,  to  be  Valvata  utahensis  and  Sphm- 
ium,  striatinum,  and  reported  by  him  to  be  characteristic  "  fresh- 
water shells  living  in  still  water  and  muddy  bottom."  This  would 
eem  to  indicate  that  at  the  time  these  beds  were  deposited  the  waters 
>f  Lake  Bonneville  were  fresh  and  possibly  had  not  become  an 
ticlosed  inland  sea.  The  chief  scientific  value  of  this  dee])  boring  is 
o  show  that  the  unconsolidated  deposits  are  here  at  least  2,000  feet 
hick,  and  thus  that  the  base  of  the  great  western  fault  scarp  or  front 
f  the  Wasatch  Range  and  the  bed-rock  floor  underlying  the  recent 
jeposits  in  this  basin  are  more  than  2,000  feet  below  the  present  land 
urface.  This  boring  proves  that  oil  does  not  occur  in  the  vicinity 
n  the  beds  cut. 
ASPHALT. 
The  onty  occurrence  of  asphalt  known   in  this  region  is  in  the 
orthwest  part  of  Great  Salt  Lake,  at  the  Rozel  Hills.     The  nearest 
lilway  station  is  Rozel,   10  miles  north,  but  the  most  convenient 
arting   point    is   Promontory,   on    the   Southern    Pacific    Railway. 
rom  that  point  in  the  Promontory  Range  a  drive  of  15  miles  south- 
estward    across   the   intermontane   desert    known    as   Rozel    Flats, 
ings  one  to  the  southern  end  of  the  Rozel  Hills,  at  their  descent  to 
lit  Lake.     The  region  is  topographically  a  portion  of  this  desert, 
hich  extends  westward  athwart  the  course  of  the  Rozel  Basin  Range. 
The  geology  of  the  region  is  little  known.     The  Promontory  and 
ozel  ranges  are  made  up  mainly  of  well-bedded   calcareous  sedi- 
ents,  which  have  been  deformed,  folded,  and  broken.     At  the  south 
d  of  th.e  Promontory  Range,  along  the  route  of  the  new  Lucin 
t-off,  are  steeply  tilted  schists  and  gneisses,  which  doubtless  form 
e  foundation  for  the  sediments,  while  extensive  masses  of  a  basic 
trusive  cap  the  Rozel   Hills  and   indicate   a  late  eruption.     The 
limentary  beds,  according  to  the  geologists  of  the  Fortieth  Parallel 
irvey,  are  of  Carboniferous  age,  a  conclusion  reached  by  general 
"relation  of  the  strata  here  with  those  of  the  Promontory  Range. 
Ai:  the  south  end  of  the  Rozel  Hills  the  buff  and  gray  limestones 
i  much  silicified  and  metamorphosed.     They  have  been  crumpled 
o  a  series  of  broad  folds  and  much  broken  and  brecciated.     An 
Imsive  body  of  a  basic  extrusive  with  amygdaloidal  structure  forms 
crest  of  the  hills.  This  was  believed  by  the  observers  of  the  For- 
h  Parallel  Survey  to  be  "the  same  flow,  now  separated  by  the 
Baternary  deposits  of  the  valleys,11  that  outcrops  to  the  north,  on 
t}|  Hanzel  Mountains,  and  also  to  the  west  of  the  lake,  on  the  hills 
ait  north  of  the  Terrace  Range.     It  is  quite  possible  that  this  exten- 
