92 THE GEOLOGY OF PRI^STCE GEORGE^S COUNTY 



It dips under the overlying strata and is believed to extend over the 

 entire central and eastern area of the county beneath the younger 

 formations. 



Character of Materials. — The Earitan consists of variable mate- 

 rials similar to those composing the Patapsco formation except that, 

 in general, the clays are not so highly colored. White and buff sands ; 

 stratified sandy clays, light chocolate in color, in places containing 

 leaf impressions ; light-colored argillaceous sands and sandy clays 

 (''fuller's earth") ; and white, yellow, drab, bluish drab, and varie- 

 gated clays all occur in deposits of this age. The drab clays are 

 here and there lignitic and pyritiferous, and in places exhibit part- 

 ings of sand indurated with mammillary limonite. Ledges of sand- 

 stone, indurated by iron oxide or silica, are common. One and one- 

 quarter miles north of Collington M'hite quartzitic sandstones repre- 

 sent this phase. Several acres are covered with these masses of hard 

 rock, which have been used for structural purposes in the vicinity. 

 Similar sandstones of Raritan age occur in several places in Anne 

 Arundel and Baltimore counties. The light-colored sands show in 

 many localities large blotches of red ocher, locally designated as 

 ''paint pots." The Earitan deposits can not everywhere be separated 

 with ease from the underlying Patapsco strata, but there is much 

 less difficulty in separating them from those of the overlying Mag- 

 othy formation, which are much more uniform in character and less 

 highly colored. 



Palcontologic Character. — Both animal and plant remains have 

 been found in the Raritan formation, but the known fauna is very 

 scanty both in individuals and species, the flora being much more 

 abundant. Logs of lignitized conifers exhibiting teredo borings have 

 occasionally been found, and in jSTew Jersey this formation has 

 yielded some bones of a plesiosaur and various molluscan remains. 

 No dinosaurian remains have thus far been found in Raritan strata. 



The flora of the formation includes ferns, fronds of cycads, coni- 

 fers, monocotyledons, and dicotyledons, the last-named being partic- 

 ularly conspicuous and relatively modern in aspect. The Raritan 



