Maryland Geological Survey 51 



greatest thickness in the northern Atlantic Coastal Plain and where they 

 have been differentiated into a larger number of stratigraphic units than 

 are recognizable in Maryland. The gradual transgression of the Tertiary 

 deposits southward has also covered the uppermost formations of the 

 ISTew Jersey area which have not been recognized southwest of the Dela- 

 ware line. 



The Upper Cretaceous strata consist of sands, clays, and marls, the 

 latter both calcareous and glauconitic. The marls, especially the green- 

 sand marls, are confined to the higher formations of the Upper Cre- 

 taceous and are most extensively developed in the Monmouth formation, 

 where the beds are at times highly glauconitic. The strata are rarely 

 consolidated, although indurated beds are found in the Earitan where 

 they constitute the ledges at Rocky Point at the mouth of Back Eiver, 

 Baltimore County, and at the White Eocks, and on Stony and Eock creeks, 

 Anne Arundel County. Indurated beds are also found in the Magothy 

 formation on Magothy Eiver, and less frequently in the Matawan and 

 Monmouth formations, although here and there inconspicuous layers are 

 developed in these formations both on the Eastern and Western shores. 



The strata have in general a progressively lower dip to the southeast- 

 ward in passing upward in the series, the dip varying from 30 feet to 

 35 feet in the mile in the lowest formation to not over 25 feet in the mile 

 in the highest. The deposits apparently thicken slightly down the dip, 

 although they probably thin farther to the seaward, as already discussed 

 in the case of the Lower Cretaceous strata. 



The stratigraphic relations do not indicate any marked unconformities 

 beyond the gradual transgression of each succeeding formation over the 

 preceding formation southward, although the Monmouth formation over- 

 laps the Matawan entirely in central Prince George's County and overlies 

 the Magothy formation directly for a considerable distance in this area. 

 The materials comprising the several formations are, however, in the 

 main more or less distinctive, and it is probable that considerable time 

 intervals mark the stratigraphic breaks. 



The Earitan and Magothy formations are of epicontinental origin, the 

 marine waters nowhere reaching the area of recognized deposition in 



