382 Scientific Intelligence. 



the lowest beds of the Eocene in Xorth America. 



.f^raphy of the respective continents at that \iVY\o 

 bv the affinity of the fossils as regards their peculi 

 acters. Thus tlie j^^enus Lnxopleurun Meek orio-i 

 out \vith the ohler" Eocene fauna. This was als^ 

 Vi'Joritina ?,reek, a [?enus closely allied to if not \ 



rate sect 



\on {C. Tngones). He 



^ descril 



)es'te]i sp, 



ba^in an( 



1 Matheron .mk 



■ from 1 





^[(\<!}oh 



is unkno 



wn in later Eo 





ata. '!v 





Melaniida^ cannot !)e . 



^'nam!^ 



she<t -t 



■lESally 



Lignite \ 



.edsofrrovenc 



I jWd'fn 





This is 



the Tla..f {P>, 



)l,Hi;fer 



II) hmn 



^^r>ie 



charactei 



rized genus, v( 



■v.:^: 





11 Thn-a 



related t 





It is 



also limii 



Eocene, 



and tv^s' pr^.: 



Zz 







although 



its nearest li 



•m is f 



;/!•''/).''" 0-. 



inhabits 



the Ped.-o T^,n 



mca riv 



(;r, Bah 



ia." /.o." 



related c 



)n one side to 



Cfstcf/l. 



'I aTid . 





which la 





arently 



became 



"e\tiiict"i 



era, for ii 



t i>^nnk,^wi^ll! 



Tertiar 



y forma 



tions. and 



The marine ecpiivak'nt 'of'this' lower Sn-e no' format ion 

 bly to be found in the <livision 13, of Mr. Gabb's Crelaccc 

 of Caiitoiuia. 



The hydrogra])hy of this early Tertiary era ma\- he 

 from the foregoiTi<r statement to have been a river -X'^tt 

 gous to that of Hrazil at the i)resent time. The pri-i-nc 

 number.-, of estuarv shells forbids us to suppose thai t: 

 inhabited lakes rafhor than livers which ro^e in not ur 

 vated hills ^or mountains, except as isolated i>e:iks, ha 

 been develoi)ed at this period, when tlH> iiivat basin oi 1 

 submeroed, and the Mississippi valley and its ri\ers wen 



The ele^ation of this vast reo-ion to anv 0( 



.nsidc-ai)!; i^' 



place in tlie first sta-e of the Eocene era, : 



"•Urs'^e^ha 



at the great extent of such brackish water 





glance at a similar rivor svstem 2,200 mik 



TyxTxCx^^ 



tlie rise of the Cretaceous 'formation, this c 



ondition of tl 



was formed, and as no transition beds ar 



e kuo.-., th<. 



now genera and species so ditierent from v 

 an unexplainerl phenomenon in the ocolooi 



vhat had live. 



cal history of 



So far in Europe, Tbclieve, no auriu-ntic 



account has 



lishcd of anv fos>iIiferous beds bitueuitb 



e lou-er Eoce. 



Cretaceous strata, that would indicate a tr 



■u.sition perio 



