58 The Upper Cretaceous Deposits of Maryland 



occur in irregular lenses at various horizons. These coarse beds are often 

 so firmly cemented by hydroxide of iron that they have been employed 

 locally for rough structural purposes. On Elk Neck rain pillars capped 

 by indurated masses have been observed. 



Sandy clays and clays occur as lenses at all horizons, the latter in very 

 variable colors, at times white, but more frequently yellow, drab, or 

 highly variegated, in this latter case being similar to the variegated clays 

 of the Patapsco formation. Such clays are well exposed in the high bluffs 

 at Worton Point, Kent County. The darker clays are at times lignitic 

 and pyritic ; and also contain small nodules of iron carbonate. The clays 

 in places show thin partings of sand at regular or irregular intervals, 

 which when near together give the clay a fissile character. At times 

 isolated patches very rich in iron oxide are locally known as " Paint Pots," 

 while the highly variegated layers of clay, also rich in iron oxide, have 

 been referred to as " Peach Blossom Clays." 



The deposits of the Earitan formation are in the main quite distinct 

 from those of the underlying Patapsco formation, but are more nearly 

 like those of the Magothy formation which, however, lacks the highly 

 colored beds that are found here and there in the Earitan. At the same 

 time the Magothy formation consists more largely of definitely stratified 

 layers which betoken the beginning of the more distinctly open water 

 stratification of the later Cretaceous formations. 



Strike, Dip, and Thickness. — The strike of the Earitan formation is 

 in a general northeast-southwest direction, becoming nearly north and 

 south in central and southern Prince George's County and in northern 

 Charles County. 



The dip of the beds is to the southeast and east at the rate of 30 feet to 

 35 feet in the mile, although it is somewhat greater in the outliers to the 

 west of the main body of the outcrop nearer to the " fall-line." 



The maximum thickness of the formation probably does not exceed 

 250 feet in the area of outcrop and generally is less than 200 feet, although 

 this thickness is oftentimes not reached even in the northern part of the 

 district where the chief development of the formation occurs. Farther 

 south the thickness gradually declines until in Anne Arundel County it 



