ILLUSTRATIONS 



PLATE FACING PAGE 



XIX. Pig. 1. — View showing Scrub Pine and Black Jack Oak on the 



Susquehanna Clay, near Bowie, Prince George's County... 206 



Fig. 2. — View showing rocky slopes with pure stand of Hem- 

 lock along the Patapsco River, near Northbranch, Balti- 

 more County 206 



XX. Fig. 1. — View showing Serpentine Barren with Black Jack 



and Post Oak, Soldier's Delight, Baltimore County 214 



Fig. 2. — View showing the thin soil covering on the topland 

 of the Serpentine Barrens with flowering clumps of Field 



Chickweed, Soldier's Delight, Baltimore County 214 



XXI. Fig. 1. — View showing edge of forest in the Serpentine 

 Barrens with Black Jack Oak, Post Oak, and Scrub Pine, 

 near Gaithersburg, Montgomery County 222 



Fig. 2. — View showing low undergrowth with ferns character- 

 istic of moist humus soils in the upper Midland District, 



near Hancock, Washington County 222 



XXII. Fig. 1. — View showing forest typical of rich slopes with Oak, 

 Tulip Tree, Yellow Locust, White Pine, Black Gum, and 

 Hornbeam, near Clear Spring, Washington County 230 



Fig. 2. — View showing moist forest with undergrowth of 

 Smilax, Osmunda, Habenaria, and Pogonia, near Wolfsville, 



Frederick County. 230 



XXIII. Fig. 1. — View showing upper Midland topography in the 



vicinity of Parr's Ridge, near Westminster, Carroll County. 238 



Fig. 2. — View showing vegetation on the cut-over summit of 

 Catoctin Mountain with Scrub Oak, Scrub Pine, Laurel, 



Baptisia, and Sweet fern 238 



XXIV. Fig. 1. — View showing roadside on upper slopes of Catoctin 

 Mountain with Scrub Pine, Chestnut Oak, Laurel, and 

 Sweet fern 24G 



Fig. 2. — View showing the Potomac River near Harper's 



Ferry with Dianthera along the bank 24G 



XXV. Fig. 1. — View showing the Chesapeake and Ohio Canal near 

 Hancock and the character of the vegetation along the 

 banks 254 



Fig. 2. — View showing forest characteristic of thin soils in 

 the lower 1 Blue Ridge with Black Jack Oak, Red Cedar, 



and Pitch Pine, near Dargan, Washington County 254 



XXVL Fig. 1. — View showing a Rock River with Umbilicaria and 



other lichens, near Buena Vista, Frederick County 262 



Fig. 2. — View showing Talus Rocks in forest, near Pen Mar, 



Washington County 262 



XXVII. Fig. 1. — View showing pure stand of Red Cedar near Conoco- 



cheague Creek, Broad Fording, Washington County 270 



Fig. 2. — View showing the western margin of the Hagers- 

 town Valley, near Clear Spring, Washington County 270 



