62 AMERICAN FOSSIL BRYOZOA. fBuiL.lT.r 



Oroniretepora D'Orbigny. Not recognized. 



Orbitulites Eichwald (preoccupied). Now Orbipora Eichwald. 



Penniretepora D'Orbigny. Not recognized. 



Pileotrypa Hall=Eridopora Ulrich. 



Pinnaporella Simpson (1895)=Ptiloporina Hall. 



Pinnaporella Simpson (1897)=Ptiloporella Hall. 



Pinnaporina Simpson =Ptiloporina Hall. 



Polyporella Simpson=Polypora McCoy. 



Protoretepora De Koninck=Polypora McCoy. 



Pteropora Hall=T;«niopora Nicholson. 



Ptilionella Hall=Reptaria Rolle. 



Ptychonema Hall and Simpson =Monotrypa Nicholson. 



Reteporella Simpson^Reteporidra. 



Rosacilla Roemer=Berenicea Lamouroux. 



Sagenella Hall=Berenicea Lamouroux. 



Stictocella Simpson=Cystodictya Ulrich. 



Stictoporidra Simpson =Tpeniopora Nicholson. 



Subretepora D'Orbigny. Not recognized. 



Tabulipora Young =Stenopora Lonsdale. 



Tectulipora Hall=Loculipora Hall. 



Tectuliporella Simpson =Isotrypa Hall. 



Thamnocella Simpson =Drymotrypa Ulrich. 



Thamnopora Hall (preoccupied). Now Thamnotrypa Hall. 



Tubuliclidia Lonsdale =Stenopora Lonsdale. 



DISTRIBUTION^. 



GEOGRAPHIC DISTRIBUTION 



The most favored part of the earth for reading Paleozoic history is 

 the continent of North America. On this continent the deposition of 

 sediments proceeded under such fortunate conditions in the Paleozoic 

 ages and the sediments have since been so little disturbed that their suc- 

 cession is easil}" made out. A large inland sea occupied the interior of the 

 continent flanked on the east and west by more or less continuing bar- 

 riers. The wide area of this sea, coupled with its comparative shallow- 

 ness, provided conditions highly favorable for an abundant marine life, 

 and especially for bryozoa. In the region of the eastern barrier, now 

 the eastern highland of the continent, judging from the fossil remains 

 hitherto made known, the conditions were often, perhaps generally, 

 unfavorable for bryozoan life and only locally are the remains of this 

 class found in the Paleozoic rocks of the Appalachian region; but the 

 wide sea stretching for a thousand or more miles westward from the 

 eastern barrier, gradually filling with the detritus from the earlier- 

 formed or primeval rocks, supported a wealth of marine forms, among 

 which the bryozoa formed a leading element. 



The Eurasian land mass presents many surface exposures of Paleozoic 

 age, but they are to a greater or less extent disconnected. In Asia the 

 Salt Range of India has yielded Carboniferous bryozoa with its other 

 fossils. The region of the Ural Mountains, the regions bordering upon 



