162 
The ATYierican Geologist. 
March, 189a 
Paleozoic. 
Mesozoic. 
C.«NOZOIC. 
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? Mesotreta, Kutorga. 
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': Volborthia, von Moller. 
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Fain. SiPHONOTHETID.K. 
— 
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SiphoMotret;i, dc Vernt-iiil. 

^^ 
Schizambon, Walcott. 
— 

■/ Key^;('l■liMt;la, Pander. 

y Helmerseiiia, Pander. 
— 
Fam. Craniid.e. 
1 
— " 
— 
— 
»_> 
^— 
-— 
^— 
Crania, Retzins. 

~~~ 
— — 




^~~ 
Oraniella, (Ehlert. 
'■' 
i 
Cardinocrania, Waasjon. 
1 

Ancistrocrania. Dall. 
1 

Craniscns, Dall. 
Pholidops, Hall. 
—— 


-^— 
Pseudocrania, McCoy. 

Fam. KuTOB(;iNiD.E. 
— 
Kutorgina, Billings. 
"~"~ 
Schizopholi:^, Waagfii. 
Fam. Clitambonitid.k. 
— ^ 
— " 
^^^mm 
Clitanibonite8, Piinder. 

1 
Polytfvchia, Hall. 

Protorthis, Hall. 
■~~~ 
Hemipronites!, Pander. 
•~~" 
Scenidinm, Hall. 
Fam. Pentamerid.-e. 
-^ 
"— 
— 
— 
^— 
Camarella(part), Billings. 
^~~ 
"■^ 
Anastrophia, Hall. 
~~~ 
Conchidium, Linne. 
~"^ 
■~~" 
Pentamerella, Hall. 

Gypidnla, Hall. 
"""• 
Amphigenia, Hall. 

Caniarophoria, King. 
~~" 
Stricklandinia, Billings. 
"^^ 
Sieberella. CEhlert. 
~^" 
Antirhynclionella, Quenstedt. 
"^"^ 
Lycophoria, Lahnsen. 
Fam. POKAMBONITII)-K. 
— ~ 
— 
Poranil)onites, Pander. 
Fam. BiLi,iN(iSELi,ii).K. 
^ 
•» 
Billingsella, Hall. 
i 
Fam. Stuopiiomenid/F.. 
— 
^b'i^b 
Subfam. Oiithotiietin.k. 
? Orthidiiini, Hall. 
"^~ 
Strophomena, Blaimille. 
^^~ 
Ortliothetes, Fi.-cher (ie Waldlieim. 
Hil)l)anony.\, \aiiii\em. 
Streptorhy'nchiis, King. 
Ka\ serella. Hall. 
])erbya, Waaijen. 
Meeki-lla, Wliito and St. .lolm. 

Tripl.'cia, Hall. 
Mimiiliis, Barrande. 
"^~' 
Streptis, David.-on. 
': ? Badiotella, BittnPr. 
1 
— III 
