Maryland Geological Survey 39 



Jersey, were discussed by the writer in an article that appeared in the 

 Bulletin of the Geological Society of America in 1894, and these con- 

 clusions are still further elaborated with the collaboration of his asso- 

 ciates in the same publication in 1897. A later statement in which com- 

 parisons are also instituted with the South Atlantic and Gulf Upper 

 Cretaceous is found in the Bulletin of the Geological Society of America 

 for 1908 and in Professional Paper No. 71 of the U. S. Geological Survey 

 for 1912. 



In later years Edward W. Berry has made a very exhaustive study of 

 the fossil plants of the Upper Cretaceous of the Atlantic Coastal Plain, 

 and many brief contributions have been made by him on various phases of 

 this subject. The results of these studies are incorporated in the exten- 

 sive discussion which he has prepared for the present volume. 



Still more recently Julia A. Gardner has been engaged in a study of 

 the animal remains from the Upper Cretaceous beds of the state, and the 

 results of her investigations are likewise published in the present volume. 



BIBLIOGEAPHY 

 1809 



Maclure, Wm. Observations on the Geology of the United States, 

 explanatory of a Geological Map. (Bead Jan. 20, 1809.) 

 Trans. Amer. Phil. Soc, o. s. vol. vi, 1908, pp. 411-428. 



1817 

 Maclure, Wm. Observations on the Geology of the United States 

 of America, with some remarks on the effect produced on the nature and 

 fertility of soils by the decomposition of the different classes of rocks. 

 With two plates. 12mo. Phila., 1817. 



1818 



Maclure, Wm. Observations on the Geology of the United States 

 of America, with some remarks on the probable effect that may be pro- 

 duced by the decomposition of the different classes of Bocks on the 

 nature and fertility of Soils. Two plates. 



Republished in Trans. Amer. Phil. Soc, vol. i, n. s., 1818, pp. 1-91. 



