. A review of the non-marine fossil mollusca of North America [microform]. Mollusks, Fossil; Mollusques fossiles. , i I NON-MARINE FOSSIL MOLLUSCA. is now occnpii'd hy the Xoitli Amciiiiiii coiitiiK'nt duriiifj; the epochs tliiit all ;>(M)l(>'iisls iijiict' ill rd'ciiinj;' to the C'lotact'ous poiiod. It can- not l>o doubted, however, that representatives of the lUniily really lived durinH that peri(td, llie remains ot'most of whitdi ar«'probably for- ever lost, but .'.ome of wliicli we may yet hope to discover. The excep- tion that has be"ii referred to is a species, tlie
. A review of the non-marine fossil mollusca of North America [microform]. Mollusks, Fossil; Mollusques fossiles. , i I NON-MARINE FOSSIL MOLLUSCA. is now occnpii'd hy the Xoitli Amciiiiiii coiitiiK'nt duriiifj; the epochs tliiit all ;>(M)l(>'iisls iijiict' ill rd'ciiinj;' to the C'lotact'ous poiiod. It can- not l>o doubted, however, that representatives of the lUniily really lived durinH that peri(td, llie remains ot'most of whitdi ar«'probably for- ever lost, but .'.ome of wliicli we may yet hope to discover. The excep- tion that has be"ii referred to is a species, tlie only kiKtwn remains of which consist of a few fra^iiiciits. too imperfect for si)ecilic charactei'i- zation, which were Ibiiiid in the I'.stnaiy de|)osit at Coalville, Utah, which has already been reicrred to as fiiriiishiiij;- Anomiapropatoriii^ixml is yet to be mentioned in connection witii certain other species. The cause of tlie ai>parent paucity of ITnione and other non-marine molluscan remains in strata of Cictaceous ajic, is not, jn-obably, that such moilusca did not then exist in very many jdaces in {jreater or less abundance; but it is jnobably due to tlie tact that few of the non-marine deposits (»f those ei)ochs have escaped destruction. We come now to the consideration of a jicolofiical i)eriod, namely, the Laramie (which is also a reiiiarUable period of tinu' in the evolutional history of tlu' L'nioni(he), in which the physical conditions within the area now occn])ied by the Nortli Ajijeiican continent were exceedinjj'.y fiivorab'eto the existence auddevelopment of iu)n-marine niolhisca. The chief of these coinlitions was tlie wide prevalence of brackisli and fresh waters during' the whole of tiiat jteriod. During tlm Ijaramie period there existed a Unione fauna that, lor dilierentiatiouinto a yiient variety of subordinate types, is truly remarkable when we remember that it oc- curred at a time so remote. It is also a re!narkal)Ie fact ihat a lar,u»' proporti
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Keywords: ., bookcentury1800, bookdecade1880, bookpublisherwashi, bookyear1883
