UPPER CRETACEOUS. 87 



UPPER CRETACEOUS. 



In New Jerse}^ deposits of Upper Cretaceous age are extensively devel- 

 oped and appear at the surface over a wide belt which crosses the entire 

 State from northeast to southwest. Below the Delaware Eiver in Delaware 

 and Maryland the width of this belt gradually decreases through the over- 

 lapping of the Eocene beds and in the region of the Potomac Eiver the 

 deposits disappear entirely and have not as yet been found at the surface 

 anywhere in Virginia. That Upper Cretaceous deposits form a part of the 

 Coastal Plain of this State, however, is certain as at least five deep-well 

 borings in the vicinity of Norfolk and one at Fairport in Northumberland 

 County have revealed their presence between the Eocene and Potomac 

 deposits. Darton® estimates the total thickness of these beds to be at least 

 65 feet and possibly considerably more. The materials consist of green- 

 sand, micaceous sand, dark sandy lignitic clay, stiff clay, fine sand, coarse 

 gray sand, pebbles, and shells. 



The Upper Cretaceous age of the deposits is determined by the fossils 

 which have been brought to the surface. In the Norfolk Water Works well 

 an Exogyra somewhat resembling Exogyra ponderosa was very abundant in 

 the materials penetrated between the depths of 700 and 775 feet. In the 

 well at Lambert Point, Norfolk, a bed between 563 and 610 feet yielded the 

 following forms : Exogyra ponderosa, Astarte octolirata, Ostrea plumom, 

 Gouldia (?) decemnaria, Gryphea vesicularis, Liopistha (Cymella) hella. 

 Corhula sp.. Modiolus sp., and BacuUtes (?). In the well at the Cham- 

 berlain Hotel. Old Point Comfort, fragments of Terehratula harlnni (?) 

 were obtained. 



In New Jersey the Upper Cretaceous is divided from below upward 

 into the Earitan, Magothy. Matawan, Monmouth, Eancocas, and Manasquan 

 formations, each characterized by distinct lithological and fannal features. 

 The data obtained from the few deep-well sections about Norfolk and 

 Fairport are too meagre to determine definitely just what formations are 

 present but it seems probable that more than one horizon is represented in 

 this part of Virginia. The dark sandy micaceous clays penetrated in the 

 Norfolk Water AVorks well and in the Chamberlain Hotel well resemble 

 the materials which compose so large a proportion of the Matawan forma- 

 tion in Maryland and New Jersey and the fossils from the Lambert Point 

 well are characteristic of that horizon. 



In New Jersey the fossil Terehratula harlani has been found only in the 

 Eancocas formation while the other fossils are characteristic of lower beds. 



a Darton. N. H., U. S. Geol. Survey Folio, No. 80. 



