490 CLARK AND BIBBINS 
ore.” The clays are in places dark colored, massive and 
more or less lignitic. At times they are laminated (‘slaty’’) 
and bear large numbers of leaf impressions.  Fossiliferous 
’ 
flakes and nodules of ‘‘white” and ‘‘red ore” also occasionally 
occur. The sands sometimes contain much decomposed feld- 
spar, and rounded lumps of clay are also found. The sands are 
frequently cross-bedded and give evidence of rapid deposition. 
Workable beds of ‘paint rock,” as the highly ferruginous clays 
are termed, are found at many points, usually near the base of. 
the formation. 
The strike of the formation has a general north-northeast 
south-southwest direction, following the eastern margin of the 
Piedmont Plateau. The dip of the beds is somewhat less than 
that of the underlying formations, the deposits of the Patapsco 
formation transgressing the older strata, and as a result often 
come to lie directly upon the crystalline rocks to the west- 
ward. 
A very marked unconformity is found between the deposits 
of the Patapsco and underlying formations. The thickness of 
the formation is estimated to reach fully 200 feet. 
Characteristic local sections —In addition to the several char- 
acteristic sections which have been already given, in which 
deposits of the Patapsco formation are found represented, the 
highly important locality of Cedar Hill in the area of Timber 
Neck in Anne Arundel county is also described. The section 
is on Licking Run one mile southwest of Hanover and is as 
follows: 
SECTION AT CEDAR HILL, ANNE ARUNDEL COUNTY. 
Raritan. Reddish sands, somewhat gravelly, containing “pipe ore” 12 ft. 
Patapsco. White, red and brown sands, more or less argillaceous, 
containing clay pellets” - - - - - =eeZOnLte 
Arundel. Drab colored pyritous clays with beds of lignite; pellets, 
nodules and flakes of carbonate of iron (“white ore”) Ioo ft. 
White clay (in bed of Licking Run) - - - SG lit 
Total thickness - - - - - - WOT silt 
