10 ir>r.rsTHATioxs. 



Platf". 



Jurassic cycnds from Wvoniing xi.vi-i.xiii 



Sketch map showing fossil localities of the Shasta IdirnalKin oft iililorniu i.xiv 



Ferns from the Shasta formation of California and Oregon Lxv-LXVI 



Cvcads from the Shasta formation of California and Oregon i.xvii 



Cycads and conifers from the Shasta formation of California and t)rcj;on i.xvni 



Conifei-s an<l dicotyledons from the Shasta formation of Califoinia aii<l Oregon i.xix 



Cvcadean trunk from the Shasta formation of California ixx 



Ferns from the Kootaiiic formation of Montana i.xxi 



Equiseta and cycads from the Kootanie formation of Montana Lxxii 



Cycads and conifers from the Kootanie formation of Montana and the Lakota formation 



of South Dakota i,xxiir 



Exposure of the I'otomac formation on Ontario avenue. Washington, D. C Lxxiv 



Exposure of the Potomac formation on Kansas avenue, Washington, D. C I.XXV 



Exposure of the I'olomac formation on Sixteenth street, Washington, I). C LXXVI 



Exposures of the Potomac formation at Terra Cotta, D. C Lxxvii 



Exposures of the Potomac formation at Freestone, Virginia Lxxvm 



Exposures of the Potomac formation on Back Lick Kun, Virginia Lxxix 



Map of the Potomac terrane in Maryland, the District of Columbia, and adjacent parts of 



Virginia i,xxx 



Cycad trunk and silicified wood from the Potomac of Mai viand Lxxxi 



Trunks of cycads early discovered in the Potomac of Marvland Lxxx ii-i,xxxM 



Group of cycads in the Mu.setnn of tlie Woman's College of Baltimore Lxxxvii 



View of the Link Gulch with the Link cycad in place Lxxxviir 



Group of cycads in the Museum of the Woman's College of Baltimore Lxxxix 



Cyeadeoidea niarylandica xc-xcii 



Cycadeoidea Tysoniana \<in 



Cyeadeoidea McGecana \( n 



Cycadeoidea Fontaineana xcv-xcvm 



Cyeadeoidea Goucheriana xcix 



Cycadeoidea L'hleri <■ 



Cyeadeoidea Bihbinsi ci-c iv 



Cycadeoi<lea Fisherse i v 



Cycadeoidea Clarkiana c vi 



Fossil plants from the Potomac of Virginia, the District of Columbia, and Maryland cvii-i xix 



