96 The Lower Cretaceous Deposits of Maryland 



THE aEOLOGIC PEOVINCE 



The Maryland Lower Cretaceous formations constitute part of a belt 

 of deposits of that age extending from Pennsylvania to eastern Alabama. 

 They are apparently embraced within the confines of a single geologic 

 province^ although in places transgressed by strata of Upper Cretaceous, 

 Tertiary and Quaternary age. 



The Maryland deposits afford, the most complete sequence of Lower 

 Cretaceous strata ^dthin this district. Three formations are here recog- 

 nized, each with clearly defined lithologic characters, bat separable like- 

 wise by easily recognizable unconformities. 



Characteristic plant fossils have been found both in Maryland and 

 Virginia, but are unknown elsewhere, although fragmentary plant re- 

 mains ^ are known to occur in the Alabama deposits, the Lower Cre- 

 taceous age of which has been recognized by Berry, although the mate- 

 rial thus far collected is too poorly preserved for specific determination 

 or exact correlation with other floras. 



To the northward of Maryland the Arundel and Patuxent formations 

 are gradually transgressed by the unconformably overlying Patapsco 

 formation, which in turn gradually disappears by the overlapping of the 

 Earitan formation in western New Jersey and eastern Pennsylvania, 

 except at a few localities to the west of the city of Philadelphia," where 

 outliers of the Patapsco formation have been found with distinctive lith- 

 ologic characters. 



Southward'in Virginia the Patapsco formation disappears near Fred- 

 ericksburg, except for a single outcrop of this age in the James Eiver 

 valley near City Point. The Arundel formation is not known to occur 

 south of the Potomac Eiver. With the single exception above noted, the 

 Patuxent formation is the only one exposed in south central and southern 

 Virginia, where in the valley of the James Eiver some of the most fos- 

 siliferous beds of this formation have been found. Although they are 

 separated at the surface from the deposits of the same formation farther 



^ Collected by Dr. L. W. Stephenson. 



2 Philadelphia Folio, U. S. Geological Survey, p. 9, 1909. 



