THE CALVERT FORMATION. 203 



The Calvert Formation. 



The Calvert" formation is practically continuous with deposits thus 

 iiamed in Maryland and Delaware. Both the materials and the fossils are 

 similar in the two areas although some forms are found in Maryland which 

 do not occur in Virginia and the same is true regarding a numl^er of Vir- 

 ginia species. Deposits containing similar forms are found in southern Xew 

 Jersey where they have been described under the name of Kirkwood 

 formation. 



The Calvert deposits are not known in Xorth Carolina, the St. Mary's 

 formation transgressing the Calvert before the southern limits of Virginia 

 are reached. All of the Miocene deposits in Xorth Carolina so far as known 

 belong to much more recent horizons. Dr. T. W. Vaughan"^ has identified 

 Sloan's Marks Head marl at Porter's Landing, Savannah River, Georgia, as 

 the approximate equivalent of the Calvert which would indicate the presence 

 of deposits of this age in the south Atlantic district. 



The correlation of the Atlantic coast Miocene with the Miocene deposits 

 of Europe has not been attempted .in detail and there are many points of 

 difference that make such correlation difficult. Dall states that in a general 

 way, allowing for local peculiarities, the Miocene of north Germany compares 

 well and agrees closely with that of Virginia. Berry who has determined 

 the plant remains from the Calvert formation of Virginia regards them as 

 equivalent to the middle Miocene of central Europe. 



The St. Mary's Formation. 



The St. Mary's formation contains the same materials and faunas over a 

 wide area to the north of the Hatteras axis and has been traced almost con- 

 tinuously from North Carolina across Virginia and Maryland into Delaware 

 while St. Mary's forms have also been found in the deep wells of eastern 

 Xew Jersey. The absence of the Choptank formation in Virginia brings 

 the St. Mary's fauna into sharper contract with the underlying Miocene 

 than in Maryland. The faunas are not identical in all particulars in the 

 two areas, some species found only at lower horizons in Maryland continu- 

 ing on into the St. Mary's in Virginia. 



The St. Mary's formation does not appear as far as known, to the south 

 of the Hatteras axis in Xorth Carolina but Dr. T. W. Vaughan considers 

 the Edisto beds of South Carolina as probably of the same age. 



"Science, N. S., Vol. 3L pp. 833, 834, 1910. 



