. Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean . he Carboniferous limestone. REMARKS. The fossils which Captain Pope has collected, with the exception of No. 91, are all such ascharacterize the Cretaceous formation. This formation is well represented by Grypho?a Pitcheriand Exogyra Texana from the Big springs of the Colorado. These fossils are well known inthe Cretaceous formation of Texas. The former was first described by Dr. Morton, of Phila-delphia,2 who received his specimens from
. Reports of explorations and surveys, to ascertain the most practicable and economical route for a railroad from the Mississippi River to the Pacific Ocean . he Carboniferous limestone. REMARKS. The fossils which Captain Pope has collected, with the exception of No. 91, are all such ascharacterize the Cretaceous formation. This formation is well represented by Grypho?a Pitcheriand Exogyra Texana from the Big springs of the Colorado. These fossils are well known inthe Cretaceous formation of Texas. The former was first described by Dr. Morton, of Phila-delphia,2 who received his specimens from the plains of Kiamesha, Arkansas. He also statesthat he has seen other specimens from the falls of Verdigris river, in the same territory. These fossils serve to indicate the development of the Cretaceous formation at the followingpoints: Banks of the Eed river, near Preston;*Big springs of the Colorado; Elm fork of theTrinity river; and a point twenty miles east of the Sand hills, on the Llano Estacado. I havetherefore colored these places as Cretaceous upon the map. 1 Report of Captain Pope, p. 77. 2 Mortons Syn. Org. Rem. Cret. Groups U. S., p. .... —t?^; ■ •-•^^SSi - i emu, ™r«IOCMAM)Bto rHBBKDRIVER ■ •=ssf r j . , J _ i 1 « 1 ....... L,.... L ■ . T A 0 « t r ———— ? J H 1* 