MARYLAND GEOLOGICAL SURVEY 103 



which ushered in the present cycle of events and permitted the cutting 

 of the Eecent sea-cliff. Since its initiation, the land has once more as- 

 sumed a downward motion, and the entire coast line in this region seems 

 to be sinking once more beneath the level of the waves. 



Along the shore of Chesapeake Bay and the lower courses of many 

 of its estuaries there occur at intervals deposits of greenish-blue clay 

 developed as lenses in the body of the Talbot formation. Usually the 

 base of the clay is not visible but its stratigraphic relations are such as 

 to leave no doubt that it, or a thin gravel bed on which it occasionally 

 rests, is uncomformable on whatever lies beneath. The upper siirface 

 of these clay lenses is everywhere abruptly terminated by a bed of coarse 

 sand or gravel which grades upwards into loam and at its contact with 

 the clay strongly suggests an imconformity. These clay lenses are in 

 some localities devoid, of fossils but in others they contain remains of 

 marine and estuarine animals and land plants. Many localities for these 

 clays are already known and as exploration advances new ones are fre- 

 quently discovered. Some of the more typical exposures will now be 

 described. 



Along the shore, about a mile below Bodkin Point, Anne Arundel 

 County, the variegated clays of the Earitan formation are finely exposed 

 in a cliff some 30 feet in height. These clays occupy the greater portion 

 of the section and carry an abundance of lignite more or less incrusted 

 with crystals of pyrite. Sands and gravels of the Talbot formation un- 

 conformably overlie the clays and constitute the upper portion of the cliif. 

 Half a mile farther south the cliff still maintains its former height, but 

 the section has changed. Some ancient stream must have established its 

 valley on the Earitan, for here the surface of that formation, like a great 

 concave depression, passes gradually beneath the beach to appear again 

 in the cliff 150 yards to the south. In this hollow, lying unconformably 

 on the Earitan formation, is a bed of dark-colored clay about 15 feet 

 thick. Bluish and greenish tinted bands of clay relieve somewhat its 

 somber aspect, and at about its middle portion it carries a bed of peat. 

 But its most striking feature is the presence of huge fossil cypress knees 

 and stumps which are imbedded in its lower portion. These stumps 



