38 THE CAMBRIAN AND ORDOVICIAN DEPOSITS OF MARYLAND 



1880 

 DANA, J. D. Manual of Geology. 3d ed. 



Maryland, pp. 236, 243, 419, 455, 490, 494-5. 



FRAZER, PERSIFOR, JR. The Geology of Lancaster County, Pa. 



Kept. 2d Geol. Surv., Pa., ccc. Harrisburg, 1880 atlas. 



Deals with the geological formations along the border of the state and their 

 extension into Maryland. 



LESLEY, J. P. On a slab of roofing slate covered with casts of Butho- 

 trephis flexuosa from the Peach Bottom Slate Quarries. (Read Dec., 

 1879.) 



Proc. Amer. Phil. Soc., vol. xviii, 1880, pp. 364-369. 



This paper gives the history of the find, its determination by Lesquereux, analy- 

 sis of slate and remarks by Frazer. 



. A Hudson River fossil plant in the roofing slate that is 

 associated with the chlorite slate and metamorphic limestone in Mary- 

 land, adjoining York and Lancaster counties, Pennsylvania. 



Amer. Jour. Sci., 3d ser., vol. xix, 1880, pp. 71-72. 



Buthotrephis flexuosa (determined by Lesquereux) in the Peach Bottom slates, 

 Silurian age inferred. Extract from a letter. 



1882 



SCHARF, J. T. History of Western Maryland, being a history of 

 Frederick, Montgomery, Carroll, Washington, Allegany, and Garrett 

 counties from the earliest period to the present day. 2 vols. 4to. Phila., 

 1882. . Topography and Geology by P. R. Uhler. pp. 13-46. 



1884 



FRAZER, P., JR. The Peach Bottom Slates of Southeastern York and 

 Southern Lancaster counties. 



Trans. Amer. Inst. Min. Eng., vol. xii, 1884, pp. 355-358. Plates and section. 



(Abst.) Amer. Jour. Sci., 3 ser., vol. xxix, 1884, p. 70. 



Discussion of a section along the Susquehanna River northward from the Mary- 

 land line. Also a letter from Prof. James Hall regarding the probable age of the 

 slates, which he considers are either the Hudson River or the Quebec group from the 

 presence of forms allied to Holymenites, Lamnantes lagranger and graptolithus. 



ROGERS, WILLIAM BARTON. A reprint of Annual Reports and other 

 papers on the Geology of the Virginias. Sm. 8vo. Appleton, 1884. 



