PHYSICAL COXDITIOXS IXDICATED BY THE FLORA OF THE CALVERT FORMATIOX. 



their angles of divergence depending on the rel- 

 ative width of the leaves. Texture coriaceous. 



This significant new species is rather clearly 

 marked off among previously described fossil 

 forms. Among existing forn^s its size and 

 general outhne as well as its limits of variation 

 are almost exactly those of Quercus chapmani 

 Sargent. This may he readily seen without 

 extended discussiim by the mk prints of the 

 leaves of the latter species introduced for com- 

 parison and shown in figures .3 to S of Plate XI. 



This similaritj" is, I believe, an indication of 

 relationship, and in its light the habitat of the 

 existing species becomes of special uiterest. 

 Quercus cJiapmani is a small tree, or more com- 

 monly a shrub, uihabitiog sandy barrens near 

 the coast, of rare occurrence froni South Caro- 

 lina to Florida along the Atlantic coast, reach- 

 ing its maximum of abundance and develop- 

 ment along the GuK coast of western Florida 

 from the shores of Tampa Bay to Pensacola. 

 The leaves figured come from the Santa Rosa 

 Peninsula, where it is typicaU^- developed and 

 where the environment is compara])le with that 

 of Miocene time along the shores of the shallow 

 Calvert sea. 



Occurrence: Good Hope road, Anacostia 

 Heights, D. C. 



Quercus lehmanni HoUick. 

 Plate XI. figures 9-n. 



Quercus Uhmanni. Hollick, Miocene, p. 483, figs, la, lb, 

 Man-land Geol. .Sur\-ey. 1904. 



This species was briefly described by Hol- 

 lick in 1904. Recent material collected from 

 the tjT)e locahty enables me to give the follow- 

 ing somewhat fuller characterization: 



Leaves small and narrow, oblong in general 

 outhne. Length from 21 to 38 millimeters: 

 maximum width, across the median marginal 

 lobes, from 14 to 17 millimeters. Apex 

 conically pointed. Base broadly rounded, 

 generally somewhat inequilateral. Margins 

 with one to three irregularly spaced reduced 

 lobes on each side: these lobes are more or 

 less developed, short, and conical and are little 

 more than coarse teeth; they subtend usually 

 open sinuses, although in some specimens the 

 lobes are directed upward instead of outward 

 and the sinuses are correspondingly narrow. 

 Petiole short and stout. Midrib stout, straight, 



or curved, prominent on the lower surface 

 of the leaf. Secondaries tliin, two t« four 

 pairs: thej' diverge from tlie midrib at angle- 

 of about 45' and ascend in straight or some- 

 what fle.xuous courses: a craspedodrome sec- 

 ondary runs to the tip of each lobe, and a basal 

 one on each side arches along the lower lateral 

 margin. Tertiaries obsolete. Texture coria- 

 ceous. The lobes are irregularly spacetl: if 

 there is but one on one side there are usually 

 two on the other, and if there are two on one 

 side there are tisually three on the other: they 

 may all be above the middle of the leaf, as in 

 figure 9. but often there is a small obhque one 

 lower down, as in figures 10 and 11. Midway 

 between the apex and the base, where the leaf 

 is consequently widest, they are subopposite, 

 as are the correspondmg secondaries. 



These characteristic leaves are not uncom- 

 mon, but like most of the pLint material in 

 the Calvert formation they are tisually much 

 broken. Their size, form, and texture are 

 indicative of barren soil, bright sunshine, and 

 sparse rainfall. Compared with existing spe- 

 cies they are found to resemble the toothed 

 leaves sometimes developed on Quercmt inr- 

 ffiniana Miller, a coastal species of southeastern 

 North America, which is also abundant in the 

 Pleistocene and which in the form of Quercus 

 prei-irglniana Berry is exceedhigly abundant 

 in the Phocene of the Gulf coast. Most of the 

 leaves of Quercus virginiana are oblong, 

 elhptical, or oboviite with merely undiUate 

 margins, and the significance of the occasional 

 toothed leaves is tmknown. A modem species 

 with which Quercus lehmanni may be more 

 legitimately compared is Quercus emoryi Torrey. 

 The latter has the small narrow leaves with 

 rounded bases and irregular teeth. TheA^ 

 differ somewhat from the fossil leaves m their 

 proportions, having generally a broader base, 

 but many leaves can be selected that exactly 

 match the fossil. Quercus emoryi is a stout 

 tree of the uplands of western Texas and 

 southern Xcw Mexico and Arizona, and 

 although it is not necessarily directly afiihated 

 with this iliocene form of the Atlantic coast, 

 it is not improbable that the two forms have 

 a common ancestor which once flotu-ished in 

 an intermediate area. 



Occurrence: Good Hope road, Anacostia 

 i Heights, D. C. 



