;)(j4 .Mi:S(JZ()K' FLORAS OF INrrKl) SIATFS. 



paper on the goneral sul)jpct, which ho first read before the American 

 Philosojilncal Society in Phih^delphia on .lanuarv 0. 1888." In this 

 paper he not only proposed tlie name All)irupean for the upper beds, but 

 he also proposed the name Baltimorean for the lower ones, i. e., to quote 

 his words, "for the conspicuous cla}' formation which lies near Iho bottom 

 of the alluvial column on the Archean rocks of Maryland" (see pp. 47-48). 

 It must be remembered that all who had up to that date studied the 

 foi-mation supposed that nearly, or quite all the beds in ^larylaud were 

 higher than any in Virginia, and the term "iron-ore clays," used l)y 

 Tyson, was used for the greater part of all this, although Professor Fon- 

 taine had observed that there were iUso gravels and coarse sands at 

 places in that State. Whether Professor Uhler intended his Baltimore 

 formation to extend into Virginia or not he does not say, and in this 

 paper he says that the Rappahannock freestone is lithologically different 

 from the white rocks of the Albirupean, which in fact is certainly the case. 

 He represents the iron ore as occurring in the Baltimorean across the 

 State in the foi-m of pockets. His general description of the Baltimorean 

 ma}- profitabl}' he reproduced here: 



The formation is made up of nuincrous strata, constituting altogether a column ot 

 alluvial matter more than live liundred feet deep. That part which we can examine 

 at or near the level of the lower streets in South Baltimore exiiihits a dark lead- 

 colored compact clay, well stratified, and resting immediately upon a la^er of dense 

 iron claj'-stone only a few inches hi thickness. Often the clay whicli comes in direct 

 contact with this stone is stained a bright red color, is of a very tine texture, and is 

 known as "pudding-claj-." On this the distinctly stratified layers of dark clay, 

 ranging usually from seven to nine feet in thickness, are built, and consist of strata 

 varying from three inches to fully two feet in thickness. Between the finely ground 

 layers, in contact with the smoothest surfaces, we meet with the remains of trees, 

 shrubs, vines, ferns, equisette, and, perhaps, alga. These fossil remains occur in 

 the greatest profusion, accompanied by finely reduced lignite in the upper strata. 

 At least five such intervening plant-beds are present in the base of Federal Hill and 

 its extension eastwards, in each of which some peculiar form of fern, vine, or leaf 

 serves to distinguish it IVom the others. It has lieen my good fortinu^ to discover 

 these beds in this region, and to secure ample collections of all the remains at present 

 found in them, and these are now being figured and de.scril)ed by Professor Fontaine, 

 of Virginia. 



"The Albirupean foniiation and its ucarc.'-t iclativo.s in .Maryland, by P. K. L'lilcr: Fruc. Am. Iliil. Soc, 

 Vol. XXV, pp. 42-53. 



