maryland geological survey ixv 



Geographic and Geologic Relations 



distribution of the strata 



The IVIiocene deposits of Maryland form a part of a more extensive 

 series of Tertiary beds, which extend from Massachusetts to Mexico in 

 what has been designated by Dall and Harris as the Atlantic Coast 

 Region. It is not known whether the Miocene beds in this province 

 ever extended across it in an unbroken belt, but it is' certain that the 

 processes of erosion, sedimentation and coastal movements have de- 

 stroyed much of their former continuity and that the Miocene beds are 

 now found in disconnected areas throughout the region. 



Massachusetts 

 The most northerly outcrop of Miocene beds is in the famous Gay 

 Head cliffs of Martha's Vineyard, but material which has been question- 

 ably referred to the Miocene has been dredged on Georges Bank and 

 the banks of Newfoundland, indicating, possibly, the extension of the 

 Miocene deposits indefinitely northward beneath the sea. On Martha's 

 Vineyard the Miocene beds rest uncorformably on pre-Tertiary deposits. 

 They consist of two members which are strikingly different from each 

 other in their lithologic composition. The lower member, the so-called 

 " osseous conglomerate " of Hitchcock, is a bed from 12 to 18 inches 

 thick. It is composed of medium sized pebbles of quartz, chert, calce- 

 dony and fragments of cetacean bones. The presence of these bones in 

 the formation suggested the name " osseous conglomerate." The upper 

 member which lies immediately above the osseous conglomerate, is a 

 bed of greensand . which varies in thickness from nothing to 10 feet. 

 At its base it carries rolled fragments of the under-lying stratum, 

 showing that it was deposited vmeonformably on the osseous conglom- 

 erate. 



New Jersey 



Immediately south of Martha's Vineyard the Miocene beds disappear 

 but come to the surface once more in New Jersey where they are well 

 developed in the hills south of Matawan, as well as along the coast 

 near Asbury Park. From here, uninterrupted save by shallow estuaries, 

 the Miocene beds extend southwest across New Jersey to Delaware. 



