FOSSILS OF THE MATAWAN FORMATION. 



331 



u Volutoderma woolmani, Whit. 

 ^ Rostellites nasutus, Gabb. 

 -J Rostellites angvlatus, Whit. 



s Rostellites text u rat us, Whit. 

 v Cithera crosswickensis, Whit. 

 , Alaria rostrata, Gabb. 



Anchura abrupta, Morton. 

 - Anchura compressa, Whit. 



yNatica abyssina, Morton. 



* Scalar ia sillimani, Morton. 

 ■ Turritella encrinoides, Morton. 

 Turritella vertebroides, Morton. 

 Turritella pumila, Gabb. 

 Turritella lippincotti, Whit. 

 ¥ - Modulus lapidosa, Whit. 

 Avellana bullata, Morton. 

 ^-Dentatium subarcuatum, Conrad. 

 /Dentalium falcatum, Conrad. 



3 Ammonites (Placenticeras) placenta, DeKay. ^Scaphites hippocrepis, De Kay. 

 Ammonites delawar ens is, Morton. \J Scaphites nodosus, Owen. 



Ammonites vanuxemi, Morton. 



^ Bacidites ovatus, Say. 



MONMOUTH FORMATION. 



Xame. — The Monmouth formation receives its name from the county 

 of Monmouth, in New Jersey, throughout which the deposits of this 

 horizon are most characteristically developed. A more local reason for 

 its use is found in the fact that the famous revolutionary " Monmouth 

 Battle Ground " is situated upon this formation. The name is now pro- 

 posed, for the first time, to embrace the Navesink and Redbank forma- 

 tions* of previous contributions, and to include, as well, certain sands 

 which underlie them, but which are so insignificantly developed in the 

 northern portion of New Jersey as not to have been regarded of special 

 significance at the time these formations were established and character- 

 ized. This increase in the limits of the formation has been rendered 

 necessary by the discovery throughout the southern portions of the region 

 now under consideration of conditions which render the differentiation 

 of the several members quite impossible. This division of the series still 

 holds good for the northern counties, but as a classification is sought 

 which may be strictly applicable to the entire northern Atlantic Coastal 

 plain, a revision becomes necessary, the older terms being retained to 

 designate the subdivisions wherever they occur. 



Areal distribution. — The Monmouth formation occupies the country to 

 the east of the Matawan formation and extends as a narrow belt from Rari- 

 tan ha} 7- to the valley of the Patuxent river, in southern Maryland, beyond 

 which it does not appear in association with the Matawan formation 

 except at a single doubtful locality in the valley of the Potomac river near 

 Fort Foote. In northern New Jersey the outcrop of the main body of the 

 formation increases rather rapidly from a maximum width of nearly eight 

 miles in the vicinity of the Mount Pleasant hills to barely three miles 

 at Freehold, and with the exception of marked local increases in width 



* Journal of Geology, vol. ii, pp. 164-166, 1894. 

 I,— Bull. Geol. Soc. Am., Vol. 8, 1896 



