122' Cretaceous^ 



age. There is,' then, no alternative but to accept the resnlt that s 

 Tertiary flora was contemporaneous witli a Cretaceous fauna, estab- 

 lishing an uninterrupted succession of life across what is generally 

 regarded as one of the greatest breaks in geologic time. 



He described, from the Niobrara Groa[\ of Colorado, 8yl- 

 loemus latifrons ; from the Fort Benton Group, two miles west 

 of Sibley, Kansas, Pelycoi'apis varius; from the Niobrara Group 

 or yellow chalk, near the Solomon river, Kansas, Portheus arcuatus^ 

 P. mudgei, and Pachyrhizodus leptopsis; from Ellis county, Kansas, 

 Lamna macrorhiza, L. mudgei^ and Empo merrilU; from Treoo 

 county, Empo contracta and Empo seynianceps; from the neighbor- 

 hood of Fort Wallace, Phasganodus carinatus, P. gladiolus, P. anceps,- 

 from Phillips count}'^, Tetheodus pepJiredo; from Kansas, Enchodus 

 dolichus, E. petrosus, Pelecopterus cMrurgics, Toxochelys serrifer;. 

 from Stockton, Kansas, Ptychodus janewayi; from Spring creek, in 

 Rooks county, Pelecopterus perniciosus; from the Greensand of 

 New Jersey, Osteopygis erosus, Encliodus oxytomus, E. tetraecus, Lep- 

 tomylus forfex, Diphrissa latidens, Bryactinus amorphus, Ischyodus 

 stenohryus, I. tripartitus, I. longirostris, I. incrassatus, I. gaskilli, I, 

 /ecundus, Isotosnia neoccesariensis. 



And he furnished a section of the Cretaceous rocks of the region 

 west of the Sierra Madre range of New Mexico as follows:* 



Dakota Group, 500 feet. 



Fort Benton Gruup, 2,000 feet. 



Niobrara Group, 400 feet. 



Fort Pierre Group, 1,500 feet. 



Uncertain (concealed in the Sage plain), 500 feet. 



G. K. Gilbertf found a section of the Cretaceous exposed by the 

 north fork of the Virgin river, from the vicinity of Mountain Lakelet 

 to Eockville, Southern Utah, 1,800 feet in thickness, and another on 

 the west fork of Paria creek, 935 feet. 



Prof G. F. Credner+ described, from the Cretaceous of Texas, Salenia 

 texana. 



J. J. Stephenson^ found the Cretaceous out-crop practically 

 unbroken from Golden, Colorado, to Mexico. On the west side of the 

 front or eastern range, there is a narrow area, of which only isolated 

 portions remain in Huerfano, Wet mountain, Current creek, and South 



*Proe. Acad. Nat, Sei. 

 t Geo. Sur. W. 100th Meridian, vol. 3. 

 X Zeitschrift fur d. gesammten Naturwiss. 

 I Geo. SuT. W. lOOth Meridian, vol. 3. 



