WRITINGS OF F. B. MEEK AND F. V. HAYDEN. 27 



Page. 



t Ort/io?iema, n. g., M. & W., 1861 146 



Loxonema, Fhillips, 1841 146 



i. multicostata, n. s. , M. & W., 1861 146-147 



Cephalo2)oda : 



OrtAoceras, Brcynius, 1732 147 



O. annulocostatum, n. a., M. & W.,1SG1 147 



iV^autiZMS, Bieyniua, 1732 147 



t Subgenus Trematodiscus, u. a. g., M. & W., 1861 147 



Corrections in regard to a few fossils described in papers of September and October, 1860. 



Cyatlwcrinus scitulus (September, 1860) should be 0. sculptiliis. 

 Platyostoma nana (October, 1860) should be Naticopsis. 



EuUma peracuta (October, 1860) should be ranged under Polyjihemopsis, of Portlock, probably 

 a section of the genus Loxonema. 



Orthoceras expansum (October, 1860) belongs to the geuus or subgenus Actinoceras. 

 Gyrtoceras curtum (October, 1860) should be ranged under the subgenus Aploceras. 



• 23. 



Meek, F. B. Descriptions of new Cretaceous fossils collected by the Northwestern 

 Boundary Commission oil Vancouver and Sucia Islands. <Proc. Acad. Nat. Sci. 

 Phila., v(d. xiii, pp. 314-318. 1861. Philadelphia, 1862. 



Lamellibranchiata : Page. 



Inoceramus subundatus, Meek, n. s., 1861 315 



Dosinia I tenuis, n. s.. Meek, 1861 315 



Mactra gibbsana, n. a.. Meek, 1861 , 315-316 



Cephalopoda : 



Baetdites inornatus, n. s.. Meek, 1861 316 



JBaculjtes occidentalis, n. s., Meek, 1861 316-317 



Ammonites complexus var. sueiaensis, n. a.. Meek, 1861 317 



Ammonites vancouverensis, n. s.. Meek, 1861 317-318 



Nautilus campbelU, n. s., Meek, 1861 318 



24. 



Meek, F. B., and Hayden, F. V. Descriptions of new Lower Silurian (Primordial), 

 Jurassic, Cretaceous, and Tertiary fossils, collected in Nebraska by the exploring 

 expedition under the command of Capt. Wm. F. Eaynolds, U. S. Top. Engrs., 

 with some reuiarks ou the rocks from which they were obtained. <\Proc. Acad. 

 Nat. Sci. Phila., vol. xiii, pp. 415-447. 1861. Philadelphia, 1862. 



Page. 



Lower Silurian (Primordial) rocks 415-416 



Jurassic rocks 41(5-417 



Cretaceous rocks 417-432 



Lower series 417-424 



General section of the Cretaceous rocks of Nebraska 419 



Upper Cretaceous series of Nebraska 424-432 



New Jersey section, compiled from the reports of that State 426 



Fox Hill beds 427 



Relations of the upper Cretaceous series of Nebraska to European divisions 428-432 



Tertiary rocks 432-435 



General section of the Tertiary rocks of Nebraska 433 



SILUUIAN (PKIMORUIAL) FOSSILS. 



Braehiopoda : 



Obolella, Billings 435 



O.nana, n. s., M. & H., 1861 435-436 



topflos, straight; vrj/na, thread. 



lTpijii.a and Sktkos, in allusion to the perforated umbilicus and the discoid form of the shellin the 

 typical species. 



