MARYLAND GEOLOGICAL SURVEY 55 



Marsh, O. C. Geologic and Paleontologic Investigations in Mary- 

 land. 



9th An. Rep't. U. S. Geol. Surv., 1887-88, Washington, 1889, pp. 114-115. 



The statement is made that on the evidence obtained from fossils the 

 Potomac formation has been "proved conclusively" to be "of Upper Jurassic 

 age" and that It "contains a rich and varied fauna." 



McGee, W J. The Geological Antecedents of Man in the Potomac 

 Valley. 



Amer. Anth., vol. ii, 1889, pp. 227-234. 



The conditions prevailing during the times that the Potomac and Columbia 

 deposits were being formed are described. 



Uhler, p. p. Additions to Observations on the Cretaceous and 

 Eocene Formations of Maryland. 



Trans. Md. Acad. Sci., vol. i, 1889, pp. 45-72. 



This paper contains many descriptions of Cretaceous and Eocene strata in 

 this county together with a general description of these formations as repre- 

 sented in the entire State. A list is given of all Eocene fossils recognized up 

 to that time. 



Ward. Lester F. The Geographical Distribution of Fossil Plants. 



8th An. Rept. U. S. Geol. Surv., 1886-87, Washington, 1889, pt. ii, pp. 663- 

 960, maps. 



Several localities where fossil plants have been obtained from Potomac 

 strata are mentioned. Beltsville is especially mentioned as where both fossil 

 plants and remains of dinosaurs were found in an old iron mine. 



1890. 

 Clark, AVjNL B. Third Annual Geological Expedition into South- 

 ern Maryland and Virginia. 



Johns Hopkins Univ. Cir. No. 81, vol. ix, 1890, pp. 69-71. 

 Contains a description of the Fort Washington bluff. 



Pattersox, Harry J. Report of the Chemist. 



2nd An. Rept. Md. Agri. Exper. Sta., College Park, 1890, pp. 67-94. 



The different kinds of marls occurring in Maryland are described and 

 analyses of many are given including two samples of marls from Upper 

 Marlboro and two from Piscataway Creek. 



