LIST OF THE PLATES. 
Coniferous plants from the Trias of Arizona 
Sketch map of the Little Colorado Valley, Arizona, and adjacent regions 
Sketch map of the Buck Mountain region and Cow Creek Valley, Douglas County, Oreg 
Jurassic liverworts and ferns from Oregon 
Jurassic ferns from Oregon 
Jurassic ferns and Equiseta from Oregon 
Jurassic cyeads from Oregon 
Jurassic cycads and Williamsonias from Oregon 
Jurassic Gingkos from Oregon 
Jurassic Gingkoacee and Taxacee from Oregon 
Jurassic conifers from Oregon 
Miscellaneous Jurassic plants from Oregon 
Jurasso-Cretaceous plants from Oregon and Alaska 
Jurasso-Cretaceous ferns from Cape Lisburne, Alaska 
Jurasso-Cretaceous cycads and Gingkoacew from Cape Lisburne, Alaska..........-----.----- 
Jurasso-Cretaceous conifers from Alaska, Montana, and California...........-.....-.-...--- 
Jurassic cycads from Wyoming 
Sketch map showing fossil localities of the Shasta formation of California 
Ferns from the Shasta formation of California and Oregon 
Cycads from the Shasta formation of California and Oregon 
Cyeads and conifers from the Shasta formation of California and Oregon 
Conifers and dicotyledons from the Shasta formation of California and Oregon 
Cycadean trunk from the Shasta formation of California 
Ferns from the Kootanie formation of Montana 
Equiseta and cycads from the Kootanie formation of Montana 
Cyeads and conifers from the Kootanie formation of Montana and the Lakota formation of 
South Dakota 
Exposure of the Potomac formation on Ontario avenue, Washington, D. C 
Exposure of the Potomac formation on Kansas avenue, Washington, D. C 
Exposure of the Potomac formation on Sixteenth street, Washington, D. C 
Exposures of the Potomac formation at Terra Cotta, D.C 
Exposures of the Potomac formation at Freestone, Virginia. .....-...-.-.--.---.---------- 
Exposures of the Potomac formation on Back Lick Run, Virginia.........-...-.-.--------- 
Map of the Potomac terrane in Maryland, the District of Columbia, and adjacent parts of 
Virginia 
VI 
VII-XIV 
XV 
XVI-XXVIII 
XXIX 
XXX-XXXIIL 
XXXIV 
XXXV, XXXVI 
XXXVII 
XXXVIIL 
XXXIX-XLIII 
XLIV 
XLV 
XLVI-LXIIL 
LXIV 
LXV—-LXVI 
LXVIL 
LXVIII 
LXIX 
LXX 
LXXI 
LXXII 
LXXIIL 
LXXIV 
LXXV 
LXXVI 
LXXVII 
LXXVIII 
LXXIX 
