MESOZOIC TIME — CRETACEOUS. 837 



Isocardia Washita Marcou, Inoceramus, Terehratida Choctawensis Shum. (3) The Fort 

 Worth or Washita limestone : with Terebrattila Wacoensis E., Cidaris Texana R., 

 Leiocidaris hemigranosa Shum., Holectypus planatus R., Epiaster elegans'fi\\nva.., Holaster 

 simplex Shum., Ostrea carinata Lam., Exogijra sinuata Marcou, Gryphcea Fitcheri 

 Morton, Janira Wrightii Shum., Plicatula placunea d'Orb., Pleurotomaria Austinensis 

 Shum., Lima Kimballi Gabb, Nautilus elegans Shum., Ammonites {Mortonicei'as) 

 Leonensis Con., Turrilites Brazoensis R. (4) The Denison Beds of clays and limestone: 

 having at base Exogyra arietina R., Ostrea quadruplicata Shum., Gryphasa Fitcheri R. 

 (not Morton, which is G. mucronata Gabb), the Ammonites Buchiceras inaiquiplicatum 

 Shum., Hoplite^ Deshayesi Leym., and many other species. Turhinolia Texana is 

 abundant in the western exposures of the Denison beds, and the Rhizopod, Nodosaria 

 Texana Con., occurs throughout them. 



Hill concludes from the fossils that the Trinity group is closely related in age to the 

 Wealden of Europe, and the Washita to the Lower Greensand or Gault. 



The Horsetown beds of California have afforded many species, described chiefly by Gabb 

 andTrask. Among them are : Fecten operculiformis, Fleuromya loivigata, Nemodon Van- 

 couverensis, JSferita deformis, Nerinea dispar, Neithea grandicostata, Lima Shastaensis, and 

 the Ammonites Desmoceras Breweri, Lytoceras Batesii, Fachydiscus Whitneyi, Olcoste- 

 phanus Traskii, Ancyloceras Remondi, etc. The first three Ammonites occur in the Queen 

 Charlotte group, according to Whiteaves. 



The Knoxville beds are characterized, according to the latest researches of Hyatt, 

 Stanton, and Diller, by its Aucella, Ammonites, and a few other fossils, which show close 

 relations to the Horsetown beds and a wide divergence from the Mariposa beds. 



The Fotomac beds have afforded a few rare marine shells. Whitfield mentions Astarte 

 veta, Ambonicardia Cookii, Corbicula emacerata, C. annosa {Astarte a/mosa Conrad), and 

 Gnathodon tenuides, besides 6 species of Unio and Anodonta. 



2. Upper Cretaceous. 



Plants. — In the Upper Cretaceous, leaves of Cycads are comparatively 

 rare, while those of Angiosperms are of great variety ; and to these are added 

 the leaves or fronds of Palms. 



Some of the prominent kinds in the new flora were species of Sassafras, 

 Laurus, Liriodendron (Tulip Tree), Magnolia, Aralia, Cinnamomum, Sequoia, 

 the Poplar, Willow, Maple, Birch, Chestnut, Alder, Beech, Elm, etc. A leaf 

 of a Palm (Sabal) from Vancouver Island is described by Newberry as 8 to 

 10 feet in diameter. Dawson gives an interesting review of the Sequoias in 

 his Geological History of Plants — a genus of many species then, but now 

 of only 2, and these exclusively Korth American. 



The leaves of Angiosperms, here figured, are all from the Dakota beds, or 

 their probable equivalent, on the Atlantic border, the Earitan clays of New 

 Jersey, Martha's Vineyard, and Long Island. Fig. 1369 represents a leaf 

 of Sassafraa Cretaceum Newb., of the Dakota group ; 1370, the leaf of a Tulip 

 Tree, Liriodendron Meekii Heer, from Greenland (Atane group) and the 

 Dakota; 1371, L. simplex Newb., from the Amboy clays of New Jersey, Long 

 Island, and Gay Head, Martha's Vineyard, — the figure from a leaf of the 

 latter locality ; 1372, an Andromeda, from Gay Head, a kind found also in 

 Greenland and the Dakota group ; 1373, a Myrsine of Gay Head, and likewise 

 a Greenland species; 1374, a Willow, Salix Meekii Newb., of the Dakota; 



