612 



INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



marine invertebrate fossils in the upper portion of the formation. The fauna is extensive and 

 is similar in t3rpe to that found farther north in the Magothy and Matawan formations and it 

 has also been traced throughout the south Atlantic States to the Gulf. 



The Peedee consists mainly of sands, commonly glauconitic, with subordinate beds of clay. 

 The thickness of the formation reaches about 700 feet. The Peedee carries an extensive fauna of 

 marine types, which is characterized by the introduction of Belemnitella americana and is similar 

 to the Monmouth fauna farther north. It has also been traced through the south Atlantic 

 and Gulf States. 



General remarks. — The Cretaceous deposits of the Atlantic Coastal Plain form an irregular 

 and interrupted belt along its western margin, resting for the most part on an irregularly eroded 

 surface of ancient crystalline rocks, although the sandstones and shales of the Newark group 

 intervene at some points. The slope of this floor is variable, but on the average it trends in 

 an easterly direction at an angle of about 60 feet to the mile. 



The thickness and angle of dip of the Cretaceous formations at the outcrop are extremely 

 variable owing to the differential movements which have taken place along the landward margin of 

 the Coastal Plain during the period of its building. The areas occupied by the outcrops of the 

 several formations above described gradually diminish at varying rates from the point of their 

 greatest development, until the formations finally disappear as outcropping deposits either 

 because of the differential movements during Cretaceous time or because of the transgression 

 of Tertiary and Quaternary sediments. The dip of the several formations is also variable but 

 in general grows less with each succeeding formation, the dip of the latest Cretaceous strata 

 being about 20 feet to the mile. 



The correlation of the deposits within the hmits of the northern Atlantic Coastal Plain is 

 shown in the accompanying table, together with the approximate correlation of these deposits 

 with the section hitherto recognized in the eastern Gulf region and in central Europe. L. W, 

 Stephenson and E. W. Berry, under the direction of T. Wayland Vaughan, have greatly enlarged 

 our knowledge of the stratigraphy and paleontology of the south Atlantic and Gulf States and 

 the results of their work have been available for the comparisons with the southern districts 

 south of North Carohna. 



Cretaceous formations of northern Atlantic Coastal Plain. 



