THE PHYSICAL CONDITIONS INDICATED BY THE FLORA OF THE 

CALVERT FORMATION. 

By EDWARD WILBER BERRY. 

INTRODUCTION. 

The object of the present paper is to give a 

summary of the small flora preserved in the 

Miocene diatomaceous beds of the Calvert formation in the District of Columbia and Virginia, 

and more especially to discuss its bearing on the 

physical conditions of the Calvert epoch. Subsequent to the 1niddle Eocene the next abundant marine fauna preserved along the middle 

Atlantic coast is that of the Calvert formation 

of the Chesapeake group. Although Miocene 

faunas so low in the stratigraphic column are 

known south of Virginia only in the vicinity of 

Porters Landing, Savannah River, Ga.~ closely 

related but younger Miocene faunas extend 

southward at least as far as Florida, where the 

containing formation rests unconformably on 

beds in which occur the warmer-water faunas 

of the Apalachicola group. 

The change from the Apalachicola faunas to 

those of the Miocene constitutes one of the most 

striking faunal changes of the later Tertiary in 

southeastern North America, and its emphasis 

by Dall and others has led to what I believe to 

be a misconception of the real climatic conditions of Calvert time. Likewise from the fact 

that the conspicuous deposits of diatomaceous 

ooze in existing marine waters are in the polar 

oceans it has been unscientifically assumed that 

the diatomaceous beds so characteristic of the 

Calvert formation must have been formed by 

species which had ·a more or less comparable 

environment. 

CHARACTER AND EXTENT OF THE CALVERT 

FORMATION. 

The Calvert formation, named by Shattuck 1 

in 1902 from the Calvert Cliffs, in Calvert 

County, Md., consists of 200 to 400 feet of 

1 Shattuck, G. B., The Miocene formation of Maryland: Science, new 

ser., vol.15, p. 906, 1902. 

diatomaceous earth, sandy clays, and marls. 

It is typically developed in Maryland, where the 

basal member (Fairhaven) comprises about 65 

feet of diatomaceous earth, locally argillaceous 

and showing occasional influxes of sands. The 

Calvert has been recognized in southern New 

Jersey and Delaware. It is also well represented in Virginia but disappears in the southern part of that State by the transgression of 

the St. Marys formation, which completely 

buries it in North Carolina, overlapping on the 

crystalline rocks of the Piedmont Plateau in 

some areas. 

Fossil land plants have been found in the 

Calvert at Richmond, Va., in the District of 

Columbia along the Benning road near the 

District line, and at Good Hope Hill. The 

formation crops out on the Good Hope road at 

a point near the top of the.hill, where a few feet 

of light-colored clay (Calvert) rests unconformably on the fossiliferous beds of the Magothy 

formation (Upper Cretaceous). The Calvert is 

overlain by gravels of late Tertiary or early 

Pleistocene age. This locality is one of the 

most northwesterly points at which the Calvert 

can bQ recognized with certainty, and it must 

also have been near the landward margin of the 

Calvert sea. No invertebrates are associated 

with the plants at this outcrop. 

At the Richmond locality the Calvert consists of very clayey diatomaceous earth 40 to 50 

feet in thick~ess, which rests unconformably 

upon remnants of the Eocene or upon the 

underlying Lower Cretaceous or crystalline 

rocks and is overlain by Pleistocene deposits. 

That this locality also was near the shore line 

of the Calvert sea, as it is near the landward 

limit of the existing Calvert deposits, is indicated not only by the more clayey nature of the 

materials compared with similar diatomaceous 

deposits elsewhere in the Calvert formation but 

61 
62 SHORTER. CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

by the contained plant fossils, as well as by 

considerable comminuted lignite, that in places 

forms layers 5 to 12 millimeters thick. The 

Calvert contains marine invertebrates in the 

immediate vicinity of this outcrop, and associated with the plants are Nassa peraltoides 

Martin and Discinisca lugubris (Conrad), the 

latter a species which occurs in shallow water 

free from sand. 

FAUNA OF THE CALVERT FORMATION. 

The fauna of the Calvert formation is extensive, particularly in the marls that overlie the 

diatomaceous beds. In addition to the remains of marine vertebrates, which are in general wide-ranging and of little significance in 

ecology, there is a considerable molluscan 

fauna. From the Calvert of Maryland 235 

species of Mollusca have been described. About 

100 species have been recorded from the Virginia extension of these beds, but this number 

will be considerably increased when the studies 

of Dr. J. A; Gardner are published. Twentythree of the Calvert species have been identified 

in the Florida Miocene (Jacksonville and Choctawhatchee formations), where 40 per cent of 

the fauna is common to the Chesapeake group, 

resembling more specifically the faunas of the 

Miocene formations younger than the Calvert. 

From an analyses of these Maryland faunas 

Dall,t a few years ago, concluded that they indica ted shallow marine waters and temperatures 

somewhat warmer than those of the present time 

in the latitude of Maryland. Of the species that 

persist in the existing fauna, the bulk are found 

south of Cape Hatteras. I see no reason for 

doubting Dall's conclusions, which obviously 

preclude the ''cold'' or even the ''cool temperate" conditions that have commonly been 

considered as characteristic of the Chesapeake 

group. 

The United States hydrographic charts give 

the mean temperature of the surface water of 

the Atlantic in the latitude of Maryland from 

December to May as 55°, and from June to November as 71.5°. The figures for Massachusetts Bay are 45° and 63.5°, respectively. The 

1 Dall, W. H., Maryland Geol. Survey, Miocene, pp. cxxix-clv, 1904. 

figures for the vicinity of Beaufort, N.C., which 

is immediately south of Cape Hatteras and 

which would appear to afford conditions corresponding to Dall's qualitative estimate, are 

65 + o for December to May and 76 o for June to 

November. If Dall's estimate is reasonably 

correct it would indicate that the mean annual 

temperature of the water in which the Calvert 

molluscan fauna lived was close to 70°. The 

mean for the year at the surface off the Maryland coast is 63°, and at Beaufort it is 70°, and 

although the bottom temperatures are slightly 

less than the surfac~ temperatures they are 

more uniform and for shallow seas like the Calvert would not be appreciably lower. 

FLORA OF THE CALVERT FORMATION. 

COMPOSITION AND ENVIRONMENT. 

The most abundant plant remains in the Calvert are the siliceous tests of diatoms. These 

have been much studied by diatomists, who 

have identified a very large number of species. 

I am indebted to Dr. Albert Mann for the statement that the Calvert diatom flora indicates 

a comparatively shallow, strictly marine habitat with relatively warm or subtropical tern;. 

perature. 

The remains of land plants preserved in the 

strictly marine beds of the Calvert are few both 

in number of species and in number of individuals. As a result of the present study I am 

able to enumerate 26 species-16 from Virginia 

and 17 from the District of Columbia, with 7 

forms common to the two areas. The flora includes 1 pteridophyte (Salvinia), 2 conifers 

(Taxodium and Pinus), and 23 dicotyledons. 

Leguminous forms and oaks predominate, although the cypress (Taxodium) is by far the 

most common form at Richmond, where cone 

scales and seeds as well as an abundance of the 

deciduous twigs are preserved. ~ 

Although this flora is so small it fort-q.nately 

comprises forms whose characters indicate very 

clearly the physical conditions along th~ shore 

of the Calvert sea. The accompanying table 

indicates the most similar fossil and existing 

species: 
Calvert flora. 

District of 

Columbia. 

Salvinia formosa Heer? ................. . 

Pin tis sp. . . . . . . . . . . . . . . . . . . . . . . . X 

Taxodium dubium (Sternberg) X 

Heer. 

Salix rreana Heer ....... . ....... , ....... . 

Quercus cal vertonensis Berry ... ·1 X 

Quercus lehmanni Hollick...... X 

Quercus chapmanifolia Berry .... 1 X 

Carpinus grandis Unger ......... , ....... . 

Ulmus basicordata Hollick .. . . . . I X 

Plan era ungeri Ettingshausen .... , . ...... . 

Ficus richmondensis Berry ...... , ....... . 

Platanus aceroides Goeppert ..... , ....... . 

Phyllites cercocarp ifolia Berry ... 1 X 

Cresalpinia ovalifolia Hollick ... -~ X 

Cassia toraformis Berry. . . . . . . . . X 

Podogonium virginianum Berry .1 X 

Dalbergia calvertensis Berry ..... I X 

Leguminosites calvertensis Berry 

Richmond. 

X 

X 

X 

Comparison of Calvert flora with most similar fossil and existing forms. 

Most similar fossil form. . Most similar existing form. 

Name. Horizon.a Name. 

Salvinia formosa Heer ..... l Tortonian of Baden ...... l Salvinia natans (Linne) Hoff- mann. 

Pinus treda Linne ....... . .... . 

Taxodium dubium (Stern- Eocene to Pliocene..... Taxodium distichum (Linne) 

berg) Heer. • L. C. Richard. 

Salix rreana Heer.......... Mascall formation of Ore- ............... · ............. . 

Habitat and range. 

Aquatic; widely distributed in 

Eurasia. 

Wet, coastal; 

Texas. 

Delaware to 

River swamps; Delaware to 

east Texas. 

!

Tertiary of Greenland ... } 

gon. 

X 1·......................... . . . . . . . . . . . . . . . . . . . . . . . . Quercus alba Linne ............. , Canada to Florida and Texas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quercus emoryi Torrey ....... . Arid uplands; western Texas, 

southern Arizona, and New 

X 

X 

X 

X 

X 

Some of forms referred by 

Heer to Quercus myrtilMiocene of Switzerland.! Quercus chapmani Sargent .... Mexico. 

Sandy, coastal· Georgia and 

Florida. 

loides Unger. I{Tortonian of Ellrope ... -I} 

Ca P. s a di's Unger Mascall formation of C . li . W It {Bottoms and swamps; southern r mu gr n . . . . Oregon. arpmus caro mana a er . . . Canada to Florida. 

Tertiary of Greenland .. . 

Ulmus minuta Goeppert ... Tortonian of Europe ..... Ulmus alata Michaux ......... Uplands and swamps; Virginia 

to Texas. 

Plan era ungeri Ettingshau- {Tort~:mian of Europe ..... lPI t' G r {Swamrs; North Carolina to sen. Tertiary of Greenland ... j anera aqua Ica me m · · · · · · Flonda and Texas. 

Ficus tilirefolia (Alex. Tortonian of Europe .................................. . Braun) Heer. 

Platanus aceroides Goep- {Tortonian of Baden ..... . }PI t 'd t r L' , I{Bottom lands; New England pert. Tertiary of Greenland. . . a anus occi en a lS mne · · · to Florida and Texas. 

........ , .................................................. Cercocarpus breviflorus Gray ... Dry ridges; western Texas, 

southern Arizona, New MexX 

X 

X 

Cresalpinia 

Heer. 

townshendi Tortonian of Baden ...... I Cresalpinia species ............ . 

Cassia lignitum Unger .... 1 Tortonian of Europe ..... I Cassia tora Linne ............ . 

{

Podogonium obtusifolium } Heer. . Leguminosites deperditus Tortoman of Baden ..... ·•· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · 

Heer. 

CresalpiniamicromeraHeer ..... do ................. 

1 

.... .. ........ ·: ............. . 

Pods referred by Heer to ..... do ................. Leucrena gregg1 Watson ....... . Acacia. 

ico, and Mexico. American Tropics and subtropics. 

Sandy; Virginia to Florida and 

tropical America. 

Ravines and banks; western 

Texas and Mexico. 

a Many of these forms are wide-ranging and have been identified from various horizons. Only the most similar materials are cited. 

"'0 

~ 

k:j 

Ul 

H 

0 

I> 

t'-4 

0 

0 

z 

tj 

H 

f-3 

H 

0 

z 

(/l 

z 

tj 

H 

0 

> 

f-3 

t_:lj 

tj 

t::d 

~ 

~ t_:lj 

b::j 

t-' 

0 

~ 

0 

b::j 

f-3 

~ t_:lj 

0 

> 

~ I?J 

~ 

b::j 

0 

~ 

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> f-3 

H 

0 

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C/.:1 
Comparison of Calvert flora with most similar fossil and existing forms-Continued. 

Dis- Most similar fossil form. Most similar 'existing form. 

Calvert flora. trict of J RichColum- mond. 

bia. Name. Horizon.a Name. Habitat and range. 

Rhus milleri Hollick ........... , X 

Celastrus bruckmanni Alex. __ . . . __ . Braun. 

Ilex calvertensis Berry._._. _._. X 

Berchemia priscaformis Berry __ . X 

X 

X Celastrus · bruckmanni {Tortonian of Europe .... _ } Alex. Braun. Tertiary of Greenland.__ ·---- · -- · · · · · · · ·-- · · · · ·-- · · ·-

Rhus pyrrhoo Unger . . .... 'I Tortonian of Baden._ ... !_ ... _ .. ...... .. _ .... _ . ....... . 

. .... . .. , ...... _ . _ ................. _ .. ____ . __ .... __ . _ .. __ . . I lex vomitoria Aiton .... ___ _ _ Coastal; south At1antic and 

Gulf States. 

........ Berchemia multinervis qmta!!Ian ° ranee-·· } ere emm scan ens ( 1 ) re- }Low woods; Virginia to Texail. l

Berchemia prisca Saporta .. )A · · f F B h · d H'll T 

I 

(Alex. Braun) Heer. Tortoman of Baden ... _._ lease. 

Nyssa gracilis Berry ........... -1- ...... -I X Nyssa arctica Heer ....... Tertiary of Greenland. __ Nyssa biflora Walter ........... Swamps and pond borders; 

Vaccinium cf. V. textum Heer ... Pierls scrobiculata Hollick ... ---- X 

X 

Fraxinus richmondensis Berry ... , -. - - -- - -

Phyllites sp. Hollick. _________ _ X 

Maryland to Louisiana near coast. ........ 

1 

Vaccinium textum Heer .. -J Tortonian of Baden ..... :

1 

. ........... . ... . ............ . 

.......................................................... Pieris nitida (Bartram) Ben- Wet woods; Virginia to Cuba. 

tham. 

X l

Fraxinusamericana Linne ..... ) .................................................. _, Fraxinus pennsylvanica Mar- Canada to Texas. 

shall. 

a Many of these forms are wide-ranging and have been identified from various horizons. Only the most similar materials are cited. 

.. 

~ 

~ 

~ 0 

~ 

~ 

t:r:j 

~ 

0 

0 

z 

~ 

~ 

""" t7:l 

q 

H 

..... 

0 

z 

Ul 

.., 

0 

0 

t:r:j 

z 

t:r:j 

~ t"' 

0 

t:r:j 

0 

t"' 

0 

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-.~ 

..... 

~ 

? 
PHYSICAL CONDITIONS INDICATED BY THE FLORA OF THE CALVERT FORMATION. 65 

Among the recent species with which the 

Calvert forms are compared three range as 

far .north as southern Canada and one other 

ranges into New England. On the other 

hand, all the forms, including the four just 

mentioned, range southward to Florida or 

Texas and five of these extend into the American Tropics. It is obvious that these wideranging forms are of slight value in an endeavor to estimate the climatic conditions 

along the coast in Calvert time. More significance attaches to the northern limits of 

the other existing forms with which those of 

the Calvert are compared. Three of these 

have their northern limits in southern Arizona and New Mexico, two in Georgia, two 

in North Carolina, four in Virginia, one in 

Maryland, and two in Delaware. Some of the 

comparisons with recent forms are closer or 

more significant than others. Among these 

may be cited those with Taxodium distichum, 

Quercus chapmani, Planera aquatica, Berchemia 

scandens, and Pieris nitida. Of these, the bald 

cypress (Taxodium distichum) reaches its northern limit in southern Delaware; Quercus chapmani is confined to the coast of Georgia and 

the Gulf of Mexico; Planera reaches northward 

to the Coastal Plain of North Carolina; and 

Berchemia and Pieris extend to the Coastal 

Plain of Virginia. It is obvious that if these 

comparisons are legitimate the Calvert flora 

would find its most favorable conditions for 

existence along the present south Atlantic 

and Gulf coasts. 

Another method of approach is furnished by 

comparing the Calvert flora with the contemporaneous floras of Europe. Of the 26 Calvert species, 7 are identical with and 10 are 

extremely close to forms of the Tortonian of 

Europe. The Tortonian has a very extensive 

flora, and as a result of the elaborate analysis 

by Heer it was considered to indicate a mean 

annual temperature of 65°. 

Regarding the specific environment of the 

different Calvert species, I consider the following as denizens of river or estuary swamps: 

Salvinia formosa . I Fraxinus richmondensis. 

Taxodium dubium. Pinus sp. 

. Nyssa gracilis. 

The following may be considered as dwellers 

on river bars or behind coastal sand dunes: 

Salix ra~ana. 

Ulmus basicordata. 

Cassia toraformis. 

Pieris scrobiculata. 

Platanus aceroides. 

Berchemia priscaformis. 

Carpinus grandis. 

Those which probably flourished in low bottoms, on the lower flood plains of streams, are 

Carpinus grandis. 

Planera ungeri. 

Platanus aceroides. 

Berchemia priscaformis. 

Podogonium virginianum. 

I.-eguminosites calvertensis. 

Ficus richmondensis. 

Pieris scrobiculata. 

Most of these could readily live also in river 

or estuary swamps. 

The species which may legitimately be considered to have been inhabitants of the strand 

or of coastal dunes are 

Quercus calvertonensis. 

Quercus lehmanni. 

Quercus chapmanifolia. 

Phyllites cercocarpifolia. 

Cresalpinia ovalifolia. 

Cassia toraformis. 

Dalbergia calvertensis. 

Rhus milleri. 

Ilex calvertensis. 

Vaccinium cf. V. textum. 

Celastrus bruckmanni. 

Pinus sp. 

All but Salvinia and Cassia were probably 

arborescent, and Cassia may have been. All 

the dicotyledons except Fraxinus, Carpinus, 

Platanus, Ficus, and Quercus calvertonensis 

show marked reduction of the leaf laminre, 

clearly indicating a sandy habitat or a swamp 

habitat, the latter being physiologically dry 

and in its effects much like the former. 

The leaves of the oaks, Berchemia, Podogonium, Phyllites cercocarpifolia, Dalbergia, Rhus, 

Ilex, V accinium, and Celastrus are coriaceous 

or subcoriaceous, and those of the Pieris are 

tomentose, both features tending to prevent 

transpiration and indicating a physiologically 

dry habitat as well as exposure to abundant 

sunshine. 

In comparing the two localities, that at 

Richmond clearly indicates a low coast which . 

was lined with cypress swamps and in which 

the very inconsiderable run-off carried only 

the finest muds. That in the District of Columbia, in its small-leafed oaks, Ilex, Vaccinium, Pieris, and abundance of Leguminosre, 

as clearly indicates a region of dunes comparable with the present Santa Rosa Peninsula, between Pensacola Bay and the Gulf of Mexico. 

Physical conditions may produce decided 

differences in the flora of the continental margin and the marine life of the sea which washes 

it, as for example in the English Pliocene, where 

the only avenue of immigration for terrestrial 

plants and fresh-wat er mullusks was from the 

south, while the only avenue of immigration 

for the marine fauna lay in the cool currents 

that entered the North Sea from the north. 

However, the Calvert fossils do not represent a 

northward extension of the south Atlantic and 
66 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Gulf flora along the Coastal Plain and a southward migration of a marine shallow-water fauna 

in the opposite direction along the coast, but 

both floral and faunal evidence are in accord. 

In this connection it is of interest to call 

attention to · the fact that five of the Calvert 

plants occur in the late Eocene or Oligocene 

of western Greenland, in latitude 70° N. This 

Arctic flora I believe to be .. contemporaneous 

with those more southern floras of the late 

Eocene (Jackson) or early Oligocene (Catahoula 

and Vicksburg) which are most tropical in their 

facies. It seems also to be established that 

with the gradual lowering of temperatures 

during later Tertiary time this circumpolar 

flora spread southward over North America 

and Eurasia. 

PROBABLE AGE. 

. Seven of the Calvert plants, or 26.9 per cent, 

are common to the Tortonian of Europe, and 

ten others, or 38 per cent, are represented in 

the Tortonian by very similar forms. In view 

of the fact that these floras spread into both 

regions from a common and equally accessible 

source, as I have just stated, the evidence that 

the Calvert flora indicates a Tortonian age is as 

conclusive as intercontinental correlations can 

ever be. Compared with otherAiij~t:tn-floras 

of Miocene age, that of the Calvert has little in 

common with the described Miocene floras from 

Colorado, Idaho, Oregon, or California, which 

are all lake or river valley floras of moist upland forest types. 

CONCLUSIONS. 

The Calvert flora was a coastal flora of strikingly warm-temperate affinities, comparable 

with the existing coastal floras of South Carolina and Georgia along the south Atlantic coast 

or with those along the coast of the Gulf of 

Mexico from western Florida to eastern Texas. 

The general climatic features i~ indicates are 

in accord with those which may be legitimately 

deduced. from the evidence of the marine 

faunas. The climate of the Chesapeake Miocene 

epoch, cooler undoubtedly than that of the 

Apalachicola or preceding epochs, was neither 

cold nor cool temperate. 

The age indicated by the Calvert flora is 

middle Miocene, or in terms of European 

geology Tortonian. 

NEW SPECIES OF PLANTS. 

Class GYMNOSPERMlE. 

Order CONIFERALES. 

Family PINACEl.E. 

Genus PINUS Linne. 

Pinus sp. 

Plate XII, figure 1. 

A somewhat macerated seed of Pinus of the 

Pinus tceda type occurs at Good Hope Hill. 

The material is insufficient for characterization. 

Pinus tceda Linne ranges from Delaware 

southward along the coast to Texas and extends 

up the Mississippi Valley to Tennessee and 

Arkansas. 

Class ANGIOSPERMlE. 

Order FAGALES. 

Family FAGACElE. 

Genus QUERCUS Linne. 

Quercus chapmanifolia Berry, n. sp. 

Plate XI, figures 1, 2. 

Leaves small, oblong-obovate in general outline, with a· rounded apex and a wide or narrowly cuneate, ultimately slightly rounded 

base. Length from 27 to 45 millimeters; maximum width, at or above the middle, from 14 

to 30 millimeters. Margins entire, slightly 

undulate. The lateral margins ascend to or 

above the middle, where they curve to form 

irregular and unequally developed rounded 

lobes subtending usually shallow and open 

rounded sinuses. A second short and broadly 

rounded lobe may · be developed, usually on 

only one side, in the apical region. Petiole 

short and stout enlarged proximad, 2 to 3 millimeters in length. Midrib stout, usually curved 

or flexuous, prominent on the lower surface of 

the leaf. Secondaries of varying caliber dependent on the extent to which lobes are developed; in the prominently lobed specimen 

shown in figure 2 a subopposite pair are stout 

and prominent on the lower surface of the leaf, 

where the lobation is feeble, as in figure 4. The 

secondaries are thin. There are as many craspedodrome secondaries as there are lobes-two 

or three to a leaf; the rest of the secondaries 

are camptodrome; all are somewhat irregularly 

spaced and rather straight in their courses, 
PHYSICAL CONDITIONS INDICATED BY THE FLORA OF THE CALVERT FORMATION. 6 7 

their angles of divergence depending on the relative width of the leaves. Texture coriaceous. 

This significant new species is rather clearly 

marked off among previously described fossil 

forms. Among existing forms its size and 

general outline as well as its limits of variation 

are almost exactly those of Quercus chapmani 

Sargent. This may be readily seen without 

extended discussion by the ink . prints of the 

leaves of the latter species introduced for comparison and shown in figures 3 to 8 of Plate XI. 

This similarity is, I believe, an indication of 

relationship, and in its light the habitat of the 

existing species becomes of special interest. 

Quercus chapmani is a small tree, or more commonly a shrub, inhabiting sandy barrens near 

the coast, of rare occurrence from South Carolina to Florida along the Atlantic coast, reaching its .maximum of abundance and development along the Gulf coast of western Florida 

from the shores of Tampa Bay to Pensacola. 

The leaves figured come from the Santa Rosa 

Peninsula, where it is typically developed and 

where the environment is comparable with that 

of Miocene time along the shores of the shallow 

Calvert sea. 

Occurrence: Good Hope road, Anacostia 

Heights, D. C. 

Quercus lehmanni Hollick: 

Plate XI, figures 9-11. 

Quercus lehmanni. Holllck, Miocene, p. 483, figs. la, lb, 

Maryland Geol. Survey, 1904. 

This species was briefly described by Hollick in 1904. Recent material collected from 

the type locality enables me to give the following somewhat fuller characterization: 

Leaves small and narrow, oblong in general 

outline. 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 sub tend 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 lea-f. Secondaries thin, two to four 

pairs; they diverge from the midrib at angles 

of about 45° and ascend in straight or somewhat flexuous courses; a craspedodrome secondary runs to the tip of each lobe, and a basal 

one on each side arches along the lower lateral 

margin. Tertiaries obsolete. Texture coriaceous. The lobes are irregularly spaced; 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 usually three on the other; they 

rna y all be a hove the middle of the leaf, as in 

figure 9, but often there is a small oblique 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 corresponding secondaries. 

These characteristic leaves are not uncommon, but Jike most of the plant mate:vi.al in 

the Calvert formation they are usually much 

broken. Their s.ize, forn1, and texture are 

indicative of barren soil, bright sunshine, and 

sparse raillfall. Compared with existing species they are found to resemble the toothed 

leaves sometimes developed on Quercus virginiana Miller, a coastal species of southeastern 

North America, which is also abundant in the 

Pleistocene and which in the form of Quercus 

previrginiana Berry is exceedingly abundant 

in the Pliocene of the Gulf coast. Most of the 

leaves of Quercus virginiana are oblong, 

elliptical, or obovate with merely ' unduhtte 

margins, and the significance of the occa:::;ional 

toothed leaves is unknown. A modern 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. They 

differ somewhat from the fossil leaves in 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 New Mexico and Arizona, and 

although it is not necessarily directly affiliated 

with this Miocene form of the Atlantic coast, 

it is not improbable that the two form.s have 

a common ancestor which once flourished in 

an intermediate area. 

Occurrence: Good Hope road, Anacostia 

Heights, D. C. 
68 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

Order URTICALES. 

Family ULMACElE. 

Genus ULMUS Linn~. 

Ulmus basicordata Hollick. 

Plate XII, figure 2. 

Ulmus basicordata. Hollick, Miocene, p. 484, fig. lf, 

Maryland Geol. Survey, 1904. 

This characteristically small liTmus was compared by Hollick with the cosmopolitan Planera 

ungeri Ettingshausen, especially with the type 

material 1 from the late Miocene of Austria. 

This protean and probably composite species 

has a recorded range from the Eocene to the 

Pleistocene and a geographic distribution from 

Japan and Manchuria throughout Europe to 

North America, Iceland, and Greenland. It 

has been recorded by me from the Calvert 

formation at Richmond, Va., and that material 

is certainly quite distinct from mmus basicordata, whatever may be thought of some of the 

European records of Planera ungeri. 

In my judgment Ulmus basicordata finds its 

closest European relative in mmus minuta 

Goeppert.2 This little species has been re-· 

corded from a large number of European 

localities, ranging in age from the middle Miocene to the Pliocene. The American mmus 

basicordata may be compared more particularly 

with the material of Ulmus minuta, from the 

Tortonian of Baden, on the Swiss border, described by Heer.3 

Occurrence: Richmond, Va., and Good Hope 

Hill, D. C. 

Order ROSALES. 

Family ROSACElE. 

Genus PHYLLITES of authors. 

Phyllites cercocarpifolia Berry, n. sp. 

Plate XII, figures 3, 4. 

Leaves small, obovate, with a broadly 

rounded tip and a cuneate base. Length about 

6 millimeters; maximum width, slightly above 

the middle, about 3.5 millimeters. Margins entire, possibly slightly revolute. Texture distinctly coriaceous. Petiole short and stout, 

1 Ettingshausen, Constantin, Fossile Flora von Wien, p. 14, pl. 2, 

figs. 5-18, 1851. 

2 Goeppert, H. R., Tertiare Flora von Schossnitz in Schlesien, p. 31, 

pl. 14, figs. 12-14, 1855. 

sHeer, Oswald, Flora tertiaria Helvetire, vol 2, p. 59, pl. 79, figs. 9-13, 

1856; vol. 3, p. 181, pl. 151, fig. 30, 1859. 

less than 1 millimeter in length. Midrib relatively stout and prominent. Secondaries thin 

but prominent, numerous, equally spaced and 

subparallel; about seven or eight subopposite 

pairs diverge from the midrib at acute angles 

and pursue a nearly straight ascending course 

to the margins, where they are abruptly camptodrome. Tertiaries obsolete. 

This tiny leaf suggests a relationship with 

the genus Cercocarpus, of the Rosace::B, and 

the resemblance is so great that I feel justified 

in referring the fossil to that family. Cercocarpus is a small genus of about five species 

of trees and shrubs confined to the dry interior 

. and mountainous regions of the United States 

and Mexico. The fossil greatly resembles the 

. entire leaves of Oercocarpus breviflorus Gray, a 

small tree of the pine and oak forests of the 

dry elevated ridges of southern Arizona, New 

Mexico, western Texas, and northern Mexico. 

Although I do not feel justified in referring the 

fossil to Cercocarpus without more conclusive 

evidence I believe that the resemblance noted 

indicates such a relationship. 

Occurrence: Benning road, D. C., near 

District line. 

Family ClESALPINIACElE. 

Genus CASSIA Linn~. 

Cassia toraforrnis Berry, n. sp. 

Plate XII, figures 6, 7. 

Leaflets small, sessile, inequilateral. Apex 

broad, inequilateral, slightly emarginate. Base 

broad, slightly pointed, inequilateral. · Margins 

entire. Leaf substance thin. Length about 

15 millimeters; maximum width, slightly below 

the middle, 7.5 millimeters. Midrib of medium 

size, nearly straight. Secondaries thin, about 

seven pairs, diverging from the midrib at acute 

angles, those in one-half of the lamina more 

acute, sweeping upward in ascending subparallel curves, parallel with the lower lateral 

margins, camptodrome. Tertiaries thin, of 

the Cassia type. 

This species appears to be a new species of 

Cassia, although it may represent an allied 

genus of the C::Bsalpiniace::B. Among the 

hundreds of existing species there are a number 

very similar to the fossil, which I have named 

from its resemblance to the existing Cassia 

tora Linne, an annual of sandy soils ranging 
PHYSICAL CONDITIONS INDICATED BY THE FLORA OF THE CALVERT FORMATION. 69 

from Virginia southward to Florida, Cuba, and 

tropical America. 

The fossil species are numerous and range 

from the Upper Cretaceous to the present. 

Among previously described fossil forms Cassia 

toraformis is identical with some of the leaves 

from the Tortonian of Oeningen, Baden, which 

Heer 1 refers to Cassia lignitum Unger. It is 

also very similar to Cresalpinia e.scheri Heer/ 

from Oeningen. 

Occurrence: Good Hope Hill, D. C. • 

Order SAPINDALES. 

Family ILICACElE. 

Genus ILEX Linne. 

Ilex calvertensis Berry, n. sp. 

Plate XII, figure 8. 

Leaves small, ovate in general outline, with 

a bluntly pointed apex and base, the latter 

slightly inequilateral. Length about 16.5 millimeters; maximum width, midway between 

the apex and base, about 7 millimeters. Margins entire for most of their length, apically 

with slight and remote denticulations. Texture 

subcoriaceous. Petiole short and stout, 

about 1. 75 millimeters in length. Midrib stout 

and prominent proximad, attenuated distad, 

curved. Secondaries thin; five subopposite 

pairs diverge from the midrib at wide angles 

and are conspicuously camptodrome in the 

marginal region. Tertiary venation obsolete. 

Ilex is a large genus with over 100 described 

fossil species and over 200 existing species. It 

ranges from the Upper Cretaceous to the present, and existing forms are found in all tropical 

and temperate regions except western North 

America, Australia, New Zealand, and New 

Guinea. The largest number occur in Brazil 

and Guiana. 

flex calvertensis may be compared with the 

existing flex vomitoria Aiton, a small tree of the 

coastal region of the South Atlantic and Gulf 

States. It also resembles flex vomitoriafolia 

Berry, a coastal form of the lower Eocene 

(Wilcox group) of the Mississippi embayment, 

with which it may be affiliated. 

Occurrence: Good Hope Hill, D. C. 

1 Heer, Oswald, Flora tertiaria Helvetire, vol. 3, p. 121, pl. 138, figs. 

23-28, 1859. 

2 Idem, p. 111, pl. 155, fig. 21. 

Order RHAMNALES. 

Family ltHAMNACElE. 

Genus BERCHEMIA Necker. 

Berchemia priscaformis Berry, n. sp. 

Plate XII, figures 11, 12. 

Leaves small, lanceolate, with equally acuminate apex and base. Length about 13 millimeters; maximum width between apex and the 

base, about 5.5 millimeters. Margins entire, 

slightly undulate corresponding with the camptodrome endings of the secondaries. Texture 

subcoriaceous. Petiole relatively long and 

slender, about 2 millimeters in length. Midrib 

relatively stout, somewhat curved, prominent 

on the lower surface of the leaf. Secondaries 

thin but prominent, numerous; seven or eight 

pairs diverge from midrib at regular intervals 

and acute angles, curving slightly and subparallel, camptodrome close to the margins. 

Tertiaries mostly obsolete, a few percurrent 

ones seen. 

This characteristic little species is scarcely 

distinguishable from the smaller and more 

lanceolate leaves of Berchemia scandens (Hill) 

Trelease, a high-climbing shrub frequenting 

low woods from Virginia to Florida and from 

Missouri to Texas. The genus contains about 

10 existing species, the others being natives of 

Asia and tropical Africa. About half a dozen 

fossil- species have been described. These 

include a rare form in the Aquitanian of France, 

another in the Burdigalian of Bohemia, species 

in the Pliocene of France and Holland, and the 

widespread Berchemia multinervis (Alex. Braun) 

Heer. B. multinervis has a recorded range 

from the Tongrian to the Astian throughout 

central and southern Europe. It has been identified in the lower Eocene (Raton, Denver, and 

Fort Union formations) of the Rocky Mountain province and in the Miocene of Oregon. 

The American material referred to B. multinervis is larger and wider than the Calvert 

species and has a more pronounced tertiary 

venation. Some of the smaller leaves of B. 

multinervis from European localities are much 

like B. priscaformis, as for example a leaf figured by Heer 3 from the Tortonian of Oeningen, 

Baden, which is but slightly larger or wider. 

s Idem, pl. 123, fig. 17. 
70 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1916. 

The Calvert species is named from its resemblance to Berchemia prisca Saporta,t from the 

Aquitanian of Peyriac, France, a very similar 

but slightly more oblong leaf. 

Occurrence: Good Hope Hill, D. C. 

Order ERICALES. 

Family V ACCINIACElE. 

Genus V ACCINIUM Linne. 

Vaccinium cf. V. textum Beer. 

Plate XII, figures 14, 15. 

Several specimens of a small oval subcoriaceous leaf are indistinguishable from 

Vaccinium textum Heer,Z from the Tortonian 

of Oeningen, Baden. Heer's description is 

as follows: 

V. folius subcoriaceis, ovalibus, integeiTimis, apice 

obtusiusculis, basi rotundatis; nervis secundariis camptodromis, areis reticulatis. 

The Calvert form agrees with its European 

contemporary in size, general outline, and 

texture, as well as in secondary and tertiary 

venation characters. The only difference is 

the more acute base of the American form. 

The latter feature and the wide geographic 

separation of the two occurrences have prevented the direct reference of the American 

form to Heer's species. 

1 Saporta, G. de, Etudes sur la vegetation du sudest de la France a 

l'epoque tertiaire, vol. 2, p. 338, pl. 11, fig. 1, 1866. 

2 Heer, Oswald, op. cit., p. 190, pl. 153, figs. 40-42. 

The genus contains about 125 existing species 

of wide geographic distribution, especially in 

the temperate and boreal regions of the 

Northern Hemisphere. It occurs, however, 

at high elevations in the Tropics, both north 

and south of the Equator, and evidently grew 

in intermediate areas at some past times. 

The fossil species are numerous and ranged 

from the Eocene onward, with their maximum 

display during the Miocene, when they were 

especially abundant in southern Europe along 

the shores of the Mediterranean Sea of that 

epoch. 

Occurrence: Good Hope Hill, D. C. 

Family ERICACElE. 

Genus PIERIS Don. 

Pieris scrobiculata Hollick. 

Plate XII, figure 13. 

Pieris scrobieulata. Hollick, Miocene, p. 486, tf. 1g, MarY 

land Geol. Survey, 1904. 

This species was described by Hollick from 

material obtained at the Good Hope Hill 

locality. He compared it with the existing 

Pieris nitida (Bartram) Bentham and Hooker, 

a shrub of wet woods which ranges from southeastern Virginia to Florida near the coast and 

is said to occur also in Cuba. Additional material from the type locality agrees with the 

type in outline and texture, but is only 11 

millimeters in length and 5 millimeters In 

maximum width. 

Occurrence: Good Hope Hill, D. C. 
PLATES XI-XII. 

71 
PLATE XI. 

FIGURES 1, 2. Quer<JUS chapmanifolis Berry. Good Hope Hill, D. C. 

FIGURES 3-8. Quercus chapmani Sargent. A modern form from Santa Rosa Peninsula, Fla. 

FIGURES 9-11. Quercus lehmanni Hollick. Good Hope Hill, D. C. (Figs. 9 and 11 after Hollick.) 

72 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XI 

2 

1 

3 

5 

4 6 

9 

8 10 11 

FOSSIL PLANTS FROM THE CALVERT FORMATION. 
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 98 PLATE XII 

~ ~ t ' 

' 

1 2 

3 

4 

5 

6 

8 

7 

9 

10 11 

12 

~ 14 15 

13 

FOSSIL PLANTS FROM THE CALVERT FORMATION. 
PLATE XII. 

FIGURE 1: Pinus sp. 

FIGURE 2. Ulmus basicordata Hollick. (After Hollick.) 

FIGURE 3. Phyllites cercocarpifolia Berry. 

FIGURE 4. Same, X 3. 

FIGuRE 5. Cresalpinia ovalifolia Hollick. (After Hollick.) 

FIGURE 6. Cassia toraformis Berry. 

FIGURE 7. Same, X 3. 

FIGURE 8. Ilex calvertensis Berry. 

All but figure 10 from Good Hope Hill, D. C. 

FIGURE 9. Rhus milleri Hollick. 

FIGURE 10. Same, a more lobate form from Richmond, Va. 

FIGURE 11. Berchemia priscajonnis Berry. 

FIGURE 12. Same, X 2. 

FIGURE 13. Pieris scrobiculata Holli~k. (After Hollick.) 

FIGURE 14. Vaccinium cf. V. textum Heer. 

FIGURE 15. Tip of same to show venation. 

73