MARYLAND GEOLOGICAL SURVEY 39 



WALLING, H. F. Topographical Indications of a Fault near Harper's 

 Ferry. 



(Abst.) Bull. Phil. Soc., Washington, vol. vi, 1884, pp. 30-32. 



Mentions the discontinuous extension of the Blue Ridge at Harper's Ferry in sup 

 port of increased corrugation and steepness of dip eastward with reversed folding. 

 The downthrow to the west. 



1886 



FRAZER, PERSIFOR, JR. General Notes. Sketch on the Geology of 

 York County, Pennsylvania. (Read Dec. 4, 1885.) 



Proc. Amer. Phil. Soc., Phila., vol. xxiii, 1886, pp. 391-410. 

 Discussion of the general structure equally applicable to Maryland. 



1890 



KEYES, CHARLES EOLLIN. Discovery of fossils in the limestone of 



Frederick County, Maryland. 



Johns Hopkins Univ. Cir. No. 84, vol. x, 1890, p. 32. 



Gives a geological section and description of Frederick Valley and enumerates 

 the fossils found there. 



MACFARLANE, J. R. An American Geological Railway Guide. 2d ed. 

 8vo. 426 pp. Appleton, 1890. 



Maryland notes based on data from Uhler, Williams, Fontaine and Chester. 



1891 



GEIGER, H. R., and KEITH, ARTHUR. The Structure of the Blue Ridge 

 near Harper's Ferry. (Read Dec., 1890.) 



Bull. Geol, Soc. Amer., vol. ii, 1891, pp. 155-164, plates iv and v. 



(Abst.) Amer. Geol., vol. vii, 1891, p. 262; Amer. Nat, vol. xxv, 1891, p. 658. 



The authors conclude that the sandstones are not Potsdam, as previously considered, 

 but Upper Silurian. The paper is accompanied by geological map and sections. 



KEYES, CHARLES ROLLIN. Paleozoic fossils of Maryland. 



Johns Hopkins Univ. Cir. No. 94, vol. xi, 1891, pp. 28-29. 

 Enumerates the fossils and type localities. 



. A Geologic Section across the Piedmont Plateau in Maryland. 

 Bull. Geol. Soc. Amer., vol. ii, 1891, pp. 319-322. (Published separately, 1890.) 

 (Abst.) Amer. Geol., vol. viii, 1891, p. 331. 



Besides the general treatment of the structure from Washington to Catoctin Mt., 

 there is a very brief discussion of structure of Sugar Loaf Mt. p. 322. 



