CRETACEOUS PERIOD. 479 



B. Later Cretaceous. — No. 4 (Pierre group). Upper Missouri: Nautilus 

 Dekayi, Ammonites Placenta, A.complexus, Baeulites ovatus, B. compressus, Heli- 

 roceras Mortoni, Inoceramus sublevis, Jfosasaurus Jlissouriensis. Alabama: 

 In bed a, Teredo tibialis?; in bed b, Exogyra costata, Grypheea vesicularis, 

 Inoceramus bi/ormis, Pecten b-costaUis, Nautilus Dekayi, Ammonites Placenta, 

 A. Delaicarensis, Baeulites ovatus; in bed c, Ostrea Larva, Grypheea lateralis 

 (G. Vomer), Neithea Mortoni. New Jersey: Bed a, Ammonites Placenta, Baeu- 

 lites ovatus; bed b, Aram. Delawarcnsis, A. complexus, Baeulites ovatus, Nautilus 

 Dekayi, Belemnitella mueronata ; bed c, Terebratulina 2>Hcata, Pholadomya 

 occidentalis, Ostrea Larva, Grypheea vesicularis, Exogyra costata, bones of Jlosa- 

 saurus. 



No. 5 (Fox Hills group). Upper Missouri : Nautilus Dekayi, Amm. Placenta, 

 A. lobatus, Scaphites Conradi, Baeulites ovatus, Mosasaurus Missouriensis. 

 Alabama: Exogyra costata, Gryphzca vesicularis, Nautilus Dekayi, Baeulites 

 ovatus, Scaphites Conradi. New Jersey: Montlivaltia Atlantica, Nucleolites 

 crucifer, Anancliytes ductus, A. fimbriatus, Terebratula Harlani, Grypheea lateralis, 

 G. vesicidaris, Neithea 3Iortoni. 



The New Jersey region abounds in Oysters and Exogyree, has some Ammonites, 

 Baeulites, and Echinoderms, but no Hippurites or Caprinse. 



The Upper Missouri has very few Oysters, no Exogyrse, many and large Am- 

 monites and Baeulites, but one rare Echinoderm {Hcmiaster Humpihreysianus), no 

 Brachiopods, except two Lingvlee, and no Hi2ij>urites or Caprinse. 



The Alabama resembles the New Jersey, and the Arkansas the corre- 

 sponding or middle beds of Nebraska and upper of New Jersey; but both con- 

 tain Hippurites and Echinoderms. 



The Texas region has but few species in common with the others, — Ammonites 

 vespertinus, Inoceramus latus ?, 'and /. Barabini,ihe latter being still questioned: 

 and it is characterized by Hippurites, Caprinse, Nerinscse, etc., like the Upper 

 Chalk of southern Europe. 



The species common to Nebraska and New Jersey, according to Meek & Hay- 

 den, are Nautilus Dekayi, Scaphites Conradi, Ammonites Placenta, A. complcxus, 

 A. lobatus, Baeulites ovatus, and Amauropsis paludinaefonnis. 



2. FOREIGN. 

 I. Rocks: kinds and distribution. 



The Cretaceous formation spreads across England just east of the 

 line of the Jurassic, extending north-northeastward from near Port- 

 land on the British Channel to Cambridge, and then northward to 

 Flamborough Head on the German Ocean. Like the Jurassic, 

 again, it reappears in northern France across the British Channel. 

 It also occurs in other parts of France, in Sweden, and in southern, 

 central, and western Europe. 



The rocks are (1) Sandstone, generally soft, and of various colors ; 

 (2) Marly or clayey beds ; (3) the variety of limestone called 

 Chalk, the common writing-material, in beds of great thickness ; 



