INDEX. 
547 
Page. 
Tonto,   unconformably    above   Algon- 
kian 331 
Tonto  sandstone,  Gilbert  on 331 
Powell  on . 331 
Torridon,  Geikie  on 525 
fossilsin 525 
Transition  formation  of  Bigsby 46 
rocks,  McClure  on 440 
Troost,  on  Tennessee 422 
Tuomey,  on  South  Carolina -123  421 
on  Alabama 426 
on  Primitive 470 
Tyson,  on  California 332-333 
on  Maryland... 410-411 
on  origin  of  Archean 479 
U. 
Uinta  Mts.,  Algonkian  of 297,505 
fortieth  Parallel  Survey  on. 297 
literature  of 286-289 
Unconformable  series  made  conform- 
able.  482-483,494-495 
Unconformity,  shown  by  discordance 
of  bedding 519 
shown  by  dynamic  movements 519-520 
shown  by  bedding  and  cleavage 520 
shown  by  eruptive  rocks 520-521 
shown  by  crystallization 521 
shown  by  basal  conglomerates 521-522 
shown  by  field  relations 522-523 
at  base' of  Animikie  series 176,179 
at  base  of  Keweenawan. 174,178 
at  base  of  lake  Superior  Huronian  .  174-178 
at  base  of  lake  Superior  sandstone.         157 
at  base  of  Marquette  series 175 
at  base  of  Menominee  series... 175 
at  base  of  Penokee  series 175 
at  top  of  Newfoundland  Algonkian.         251 
between  Animikie  and  lake  Supe- 
rior sandstone.  Hunt  on 59 
between  Animikie  and  Keewatiu, 
Alex.  Winchell  on 128 
between  Animikie  and  Keweenaw- 
an, McKellar  on 65 
between  Archean  and  Algonkian .  -    331, 495 
between  Archean  and  Cambrian  of 
Massachusetts 371 
between    Coldbrook    and    Coastal 
groups,  Bailey  on 235 
between  Copper-bearing  series  and 
Huronian.  Logan  on 55 
between  Copper-bearing  series  and 
lake  Superior  sandstone,  Brooks 
and  Pumpelly  on 90 
between  Copper-bearing  series  and 
Laurentian,  Macfarlane  on 56 
between  Grand  canyon  Algonkian 
and  Archean 507 
between  Grenville  and  Anorthosite 
series ... 27 
between  Huronian  and  Laurentian.      46-47 
between  Huronian  and   Potsdam, 
Murray  on... 249 
between  Huronian  and  Laurentian 
of  Penokee  district,  Wright  on.         113 
Page. 
Unconformity— Continued. 
between  Huronian  and  Laxirentian 
of  Penokee  district,  Chamberlin 
on Ill 
between  Huronian  and  Laurentian 
of  Wisconsin,  Irving  on 112 
between    Keewatin    and    Coutchi- 
ching,  Lawson  on 176 
between  Keweenawan  and  Animi- 
kie  161-162 
between  Keweenawan  and  lake  Su- 
perior sandstone,  Irving  on 147 
between  Keweenawan  and  Peno- 
kee, Irving  on '. 112-113 
between  lake  Superior  Archean  and 
Algonkian 17J-178 
between  lake  Superior   Huronian 
and  Cambrian,  Bell  on _  69 
between  lake  Superior  sandstone 
and  Copper-bearing  series,  Lo- 
gan on.. 55-56 
between  lake  Superior  sandstone 
and  Copper-bearing  series.  Mac- 
farlane on 56-57 
between  lake   Superior  sandstone 
and  Huronian.  Credner  on 90 
between  lake  Superior  sandstone 
and  Huronian,  Fulton  on.  H8 
between  lake   Superior  sandstone 
and  Keweenawan,  Irving  on  _ ..  113 
between  lake   Superior  sandstone 
and  Keweenawan,  Wooster  on.  118 
between  lake   Superior  sandstone 
and  Keweenawan t 157-160 
between  Laurentian  and  Huronian 
of  Michigan  Credner,  Irving, 
and  Wrighton ...90,97,147 
between  Montana   Algonkian  and 
Archean 505 
between  Lower  and  Upper  Hur- 
onian, Van  Hiseon 154-155 
between  Nipigon  and  Animikie,  Bell 
on 70,468 
between  Nipigon  and  Potsdam,  Bell 
on 468 
between  Silurian  and  Archean,  Dana 
on  . 447 
between  Silurian  and  Laurentian, 
Hind  on 241 
between  Tonto  and  Algonkian 331 
in  correlation 518-524 
in  correlation,  Irving  on 459  460 
in  Laurentian ..34,471 
within  Hunters  island  series Ls  1 ,  18:2 
within  Kaministiquia  series 1 8 1 , 1 82 
within  lake  Superior  Huronian 1 79-184 
within  Marquette  series 180, 182 
within  Menominee  series ...180, 181, 18k 
within  original  Huronian 498-499 
•     within  Penokee  series 181,182 
Unconformities  of  lake  Superior,  uni- 
versality of 197-198 
within  lake  Superior  Algonkian 500 
within  Grand  canyon  Algonkian. . .         507 
within  original  Huronian 184-186 
