W. B. Glarh — Brandywine Formation. 499 



Art. XXXVII. — The Brandywine Formation of the Mid- 

 dle Atlantic Coastal Plain', by William Bullock Clark. 



Name. — The name Brandywine* is proposed for this forma- 

 tion as the deposits are extensively and typically developed in 

 the vicinity of Brandywine, Prince George's County, Mary- 

 land. 



Synonymy. — (a) Appomattox formation. — The name Appo- 

 mattox was proposed by McGeef in 1888 for the older terrace 

 accumulations and various other deposits exposed in the valley 

 of the Appomattox River in Virginia. The same author;}: in 

 1890 discussed their southern extension and Darton§ in 1891 

 described the northern extension of the deposits into Maryland 

 and adjacent areas. 



The term Appomattox was used by both McGee and Darton 

 to designate two or more clearly recognizable stratigraphic 

 units separated by well defined escarpments. In McGee's 

 description of the Appomattox formation he included the two 

 higher terrace formations described by Shattuek as Lafayette 

 and Sunderland and also extended the formation down the 

 valley lines to embrace even later Pleistocene deposits includ- 

 ing parts of the Wicomico and Talbot formations, as well as 

 weathered portions of the Aquia formation of the Eocene. 



(b) The Lafayette Formation. — The name Lafayette was 

 applied by McGee|| in 1891 to the deposits of the Middle 

 Atlantic Slope which he had previously described under the 

 name Appomattox formation on the assumption that they 

 belonged to the same formation as those so designated by 

 Hilgard^f in Lafayette County, Mississippi. Hilgard's type 

 area was shown to be of Wilcox Eocene age by Berry** and 

 the work of Vanghan, Stephenson, Shaw, and others has 



* The recognition by the U. S. Geological Survey and the various State 

 Surveys in the Atlantic border area of the inappropriateness of the term 

 Lafayette as employed in the Atlantic border region has led to the proposal 

 by the author of the name Brandywine for the oldest of the terrace forma- 

 tions of that district. This name has already been submitted to the 

 Board of Geologic Names of the U. S. Geological Survey and adopted by it. 



f McGee, W. J.: Three Formations of the Middle Atlantic Slope, this 

 Journal, xxxv, 328-330, 1888. 



X Idem: Southern Extension of the Appomattox Formation, ibid., xl, 

 15-41, 1890. 



$ Darton, N. H. : The Mesozoic and Cenozoic Formations of Eastern Vir- 

 ginia and Marvland, Bull. Geol. Soc. Amer., ii, 445-447, 1891. 



I McGee, W. J. : The Lafayette Formation, 12th Ann. Rept. U. S. Geol. 

 Survey, 347-521, 1891. 



1J Hilgard, E. W.: Orange sand, Lagrange and Appomattox, Amer. Geol., 

 viii, 139-131. 1891. 



** Berry, E. W.: The age of the Type Exposures of the Lafayette Forma- 

 tion, Jour. Geol., xix, 219-256, 1911. 



