414 N. H. Darton — Magotky Formation of Maryland. 



intervals. The formation consists of the usual coarse, loosely 

 bedded sands generally white but in places stained buff or 

 pinkish. Several short thin streaks of light colored clays 

 occur and a few thin, discontinuous layers of ironstone. In 

 the base of the overlying Columbia are several masses of 

 coarse brown sandstones and conglomerate but they are sharply 

 separated from the Magothy beds. Near the entrance to Still 

 Pond a change of trend in the bluffs to southeast, carries them 

 into the Severn belt, bringing in Severn beds between the 

 Columbia and Magothy formations. In the next half mile the 

 dip carries the Magothy formation below tide level and soon 

 after, the Columbia deposits come down to the base of the bluff. 

 The Severn beds in the exposure are weathered at their base 

 to gray and lead colored clays with sandy layers ; an unusual 

 character. Higher up they are the typical black argillaceous, 

 carbonaceous sands, covered superficially with green and gray 

 sulphurous incrustations from decomposing pyrite, a common 

 feature at this region. Their relations to the Magothy beds 

 are particularly well exposed here and the gently undulating 

 erosion plane extends along the bluff in plain view for a con- 

 siderable distance. At their southeasternmost exposure in the 

 bluff the Magothy sands are steeply crossbedded, some of the 

 bedding planes having an inclination of 25°. 



South of Still Pond there are no notable exposures of 

 Magothy beds, the prominent bluff on Worton Point lying 

 west of their outcrop belt and exposing only Potomac and 

 Columbia deposits. 



Magothy River region. — The Magothy formation appears 

 first on the western shore of Chesapeake Bay on the bay shore 

 \\ miles south of Bodkin Point. The exposure is in a low 

 bluff and consists of an irregular mass of brown sandstone in 

 buff sands in all about fifteen feet thick of which the greater 

 part is sandstone. It is underlain by typical yellow and pink 

 Potomac clays along an irregular plane and dips below weath- 

 ered, but unmistakeable Severn beds exposed a short distance 

 south but not in contact. 



On the north side of the Magothy River the formation and 

 its relations are well exposed in a small side inlet, Broad Creek, 

 about three miles above the mouth of the river. To the east 

 on Gibson, and Dobbin islands and in the adjoining higher 

 lands notably Eagle Hill the Severn beds are extensively ex- 

 posed with all their usual characteristics. To the west up the 

 river the underlying Potomac clays and sands comes out. In 

 the inlet above referred to the contact with the Potomac forma- 

 tion is exhibited in a long low bank and the line of uncon- 

 formity is seen to be unusually irregularly and strikingly dis- 

 tinct. The Magothy beds are the usual coarse gray, loosely 



