ILLUSTRATIONS.

	PLATE	FACING	PAGE
	I.	View of Model of the State of Maryland............................	23
	II.	The Potomac River Valley at Williamsport, on the Western Maryland Railroad......................................................	64
	III.	View of the Great Valley from Blue Mountain, on the Western Maryland Railroad................................................	104
	IV.	Map showing Atlas Sheets and Charts in Maryland..................	114
	V.	Map showing leading Triangulation in Maryland....................	122
	VI.	Hypsometric Map of Maryland....................................	142
	VII.	View showing Estuary of the Chesapeake Bay near Queenstown......	146
	VIII.	The Falls of the Potomac..........................................	148
	IX.	View of the Youghiogheny Valley in the Alleghany Mountains, on the Baltimore and Ohio Railroad..................................	152
	X.	The Gorge of the Potomac at Harper's Ferry looking east, on the Baltimore and Ohio Railroad......................................	176
	XI.	Folded Strata of Lewistown Formation at Hancock, on the Baltimore and Ohio Railroad............................................	182
	XII.	View of "Devil's Backbone" in Lewistown Formation north of Cumberland, on the Baltimore and Ohio Railroad..................	186
	XIII.	Geological Map of Maryland......................................	204
	XIV.	Isogonic Map of Maryland........................................	404
	XV.	Instruments used in Magnetic Observations........................	450
	XVI.	Map showing the Preliminary Lines of Equal Magnetic Inclination and the Preliminary Lines of Equal Horizontal Force for Maryland on January 1, 1897......................................	493
	XVII.	Map showing the Lines of Equal Magnetic Declination for Maryland in the years 1700 and 1800....................................	494