710 
The American Naturalist. 
[August, 
(From the American Naturalist, August, 1889.) 
General Notes. 
GEOLOGY AND PALEONTOLOGY. 
Description of a New Genus of Corals, from the Devo- 
nian Rocks of Iowa.-Of the fossil species occurring in the Devo- 
vian rocks of Iowa, many of them are as yet new to science, which 
fact is well shown by my own cabinet of fossils, personally collected 
from these strata. Also, many species which are described and have 
long been known,to science are, in fact, but very imperfectly known. 
This is owing more particularly to th- insufficiency of material hereto- 
fore obtained. 
These statements are especially applicable to the coralline forms of 
nearly all divisions of this formation in the State. 
In this paper will be found a description of a few of these corals 
from the Independence shale and the Rockford shales of Iowa. 
Macgeea, n. gen.-Corals growing in solitary, cylindrical, some- 
times compressed, cup-shape cells; usually from five mm. to forty- 
seven mm. in length, and calyx from one and a half mm. to eighteen 
mm. in diameter; slightly curved, externally irregular, usually showing 
ing evidence of attachment. 
Calyx generally as deep as wide, but very rarely being only one-sixth 
as deep as wide; outer wall thin, rays numerous, from thirty-two to 
seventy-six in number, alternating in size within the cup. 
Costae (often very strong, and usually alternating in size) continuous 
with the rays over the edge of the cup and for some distance below 
the margin ; lower down generally interrupted, or covered with a more 
or less epithecal coat (the epi thecal coat is, however, sometimes entire- 
ly wanting), showing traces of numerous transverse partitions. Bottom 
of the cup large, and occupied by a slight depression ; rays sometimes 
very slightly twisted in the bottom of the cup. The rays, and costae 
for some distance below the margin of the cup, more or less distinctly 
denticulate on the edge. 
1'he description of this genus is based almost exclusively upon the 
species Pachyphyllum solitarium of Hall and Whitfield, although made 
also to include Macgeea culmula of this paper. This genus differs 
conspicuously from the genus Pachyphyllum (to which the specimens 
upon which this generic description is based have been referred by Geology and Palceontology. 
711 
1889.] 
Hall and Whitfield), as will be readily seen by a comparison of the 
descriptions of the two genera. This genus is named in honor of Mr. 
W. J. McGee, of the United States Geological Survey. 
Macgeea solitaria, H. and W.-Pachyphyllum solitarium H. and 
WTwenty-third Annual Report of Board of Regents on New York 
State Cabinet, page 232. The specimens referred to this species are 
often quite available, and show several important features not men- 
tioned in the original description. The denticulate character of the 
rays and costae is most usually observed only in well-preserved speci- 
mens. 
A critical examination of nearly two hundred specimens of this 
species reveals that the bottom of the calyx in well-preserved 
specimens is never occupied by a "slight elevation or columella" 
but, on the contrary, by a depression, as shown in 'Plate IX., Fig. 8, 
of the above-mentioned Report. This feature is the result ot 
weathering. 
Macgeea parva n. sp.-Coral single, very small, from five to 
six mm. in length, and from five to six mm. in greatest diameter; 
sometimes scarcely, and at other times sharply curved; subconical, 
but at times very strongly produced on the convex side of the cell, 
thus giving the calyx a distinct ovate marginal outline. 
Calyx contracted at the top, about as wide as deep; outer wall ot 
moderate thickness, bottom of the cup large. In the longitudinal section 
of a single specimen, the bottom was seen to be occupied by a very 
slight elevation ; but whether or not this is a constant feature can be 
ascertained only by securing a larger number of specimens for ex- 
amination than has as yet been obtained. 
Costae continuous with the lamellae over the margin of the cup 
and for some distance downward; lower down covered by a 
smooth, perfect epithecal coat, sometimes annulated by fine striae, 
of growth; lamellae and costae alternately large and small, some- 
times slightly denticulate on the edge (the occasional absence of 
this feature is apparently due to attrition) ; from thirty-five to forty-two 
in number. 
This species is closely related to M. solitaria of the Rockford 
shales, but differs from that species in its very small size, always con- 
tinuous, perfect, and much smoother epitheca; the relatively thicker 
outer wall, as well as the strong constriction of the upper portion of 
the cell. 
Position and locality: Blue shales below the Devonian limestone, 
Independence, Iowa. 712 
The American Naturalist. 
[August, 
Macgeea culmula, n. sp.-Coral small, elongate, cylindrical, 
slightly contracted and bent in the middle ; externally somewhat ir- 
regular ; calyx small, flattened at the bottom, width and depth about 
equal, outer wall thin; rays of moderate strength, from thirty to 
thirty-two in number. Costae continuous with the rays over the margin 
of the cup, and for a short distance below; lower down interrupted or 
covered by a continuous, perfect epi thecal coat. Costae and rays 
alternating in strength ; apparently denticulate on the edge. This 
feature, however, is not distinctly made out, owing to a slight erosion 
of the specimen. 
The specimen in hand is attached nearly full length to a fragment of 
Diphyphyllum, although not a truly parasitic species. Dimensions : 
Diameter, four mm. ; length, twenty-two mm. Position and locality: 
Rockford Shales, Hackberry, Iowa.-Clement L. Webster, Charles 
City, Iowa. 
Pohlig on Elephas Antiquus.-Professor Pohlig, of Bonn, gives 
us the result of his investigations into the characters of Elephas antiquus 
(Falconer), in 260 pages quarto, and ten quarto plates. Especial interest 
attaches to this species as the ancient representative of the African 
elephant in Europe, and on account of its annectant character to the 
typical forms of the genus. Prof. Pohlig has successfully worked out 
its entire dentition, including the smallest milk-teeth, which are the 
rarest parts of Proboscidians to be found in collections. His material 
has been mainly derived from the museums of Germany, and of Italy. 
Particularly useful are his descriptions of the first deciduous molars, 
and the deciduous superior incisors. Towards the close of the memoir 
he gives his views as to the phylogeny of the species of Elephas. He 
will not admit that the Africanus group originated from the same type 
of mastodons as the others; he even believes that it descended from 
some pre-mastodont genus. We cannot assent to this view, as it is 
evident that the Tetrabelodons include the possibility of all the species 
of elephants. 
Incidentally Prof. Pohlig expresses his views on other species of the 
genus Elephas. He thinks that a form preceded the Elephas primi- 
genius in Europe which was intermediate in characters between it and 
the E. meridionalis (Nesti), which he calls E. trogontherii. He regards 
the E. hysudricus Falc. Cautl. as identical with the E. meridionalis. 
He regards the E. militensis Falc., E. mnaidriensis Leith Adams, and 
E. falcbneri Busk, as dwarf forms of E. antiquus, due to their re- 
striction to the Mediterranean islands on which they have been found. 
He also defines a dwarf variety of the mammoth as E. primigenius 1889.] 
Geology and Palaeontology. 
713 
leith-adamsii, the remains of which are found in Germany, and are well 
represented in the museum of the University of Bonn. 
The memoir is a most important contribution to a difficult part of the 
subject, and will be welcomed by all paleontologists.-E. D. Cope. 
The Cretaceous Formation of S. W. Maryland.-For many 
years past the Tertiary formation of this section was an enigma 
which, under the light of the past, could not be satisfactorily resolved 
in accordance with the generally accepted theory that where the 
Tertiary formation was located, there was no other system to be looked 
for. 
That idea has been a stumbling block that but few have been able 
to get over in a satisfactory manner. 
The great cliff at Fort Washington, Prince George's county, has been 
to the author for the last twenty years a sealed book, an enigma not to 
be translated by any one, because, surrounded on all sides by Eocene 
deposits, it gave no sign of Eocene fossils, notwithstanding it stood up 
to an elevation of from 60 to 65 feet. 
But recent ideas suggested by the wrork and labors of Prof. Wm. B. 
Clark, of Baltimore, have thrown off the confusion and made that 
locality readable. Visiting that formation recently we found evidences 
sufficient to put it down as Cretaceous. At this cliff we found Eocene 
shells scattered around-not in situ, but amongst the fallen debris- 
sufficient to prove it was once covered with the Eocene deposit, which 
is well developed higher up both Swan Creek on the north and Pis- 
cataway Creek on the south. We found both fossils, shells, and casts, 
plants and lignite in the cliff; one plant in my collection could be 
determined by an expert, from the leaves or parts of leaves which were 
collected. 
A result of the examination of the cliff was the fact that we found it 
to rest upon a bed of variegated Jurassic clay, from one to two feet 
above high water mark, in which there is lignite. Further up Piscat- 
away creek we found years ago large coprolites, pieces of bone, sharks' 
teeth, and palates of sharks, and amber, now in the possession of Mr. 
Philip Uhler, of Baltimore. We did not then know what these meant, 
but by the light of to-day we have to admit the formation to be, con- 
trary to the generally received opinion, Cretaceous. The village of 
Piscataway is upon that formation. The old men of that place in- 
formed us that all the wells dug in that village since they could 
recollect, went down upon and into black micaceous sand and clay, 
and that they got water at from twelve to twenty feet. Traveling out 
from thence we found the Cretaceous clays covered with Eocene beds in PLATE XXXIII. 
2 
N 
2a 
Elh 
i. Monoclonius crassus. 
2. M. sphenocerus. 714 
The American Naturalist. 
[August, 
every direction ; notably so in Bond's Retreat, Prince George county. 
The Cretaceous system is found in every deep washout or gully upon 
Mattawoman Swamp for ten miles above tide water; the same is true 
of all the swamps between the Potomac and Patuxent rivers, and doubt- 
less beyond that river. Swainson's Swamp, the dividing line between 
Charles county and Prince George's county, gives Cretaceous clays over- 
laid by Miocene deposits; so does all that horizon. The Eocene and 
and Miocene can be found lapping the Cretaceous in all lower Maryland. 
Given these facts, it is in order to ask; how is it that the Cretaceous 
has not been better worked up in this region ; and why have the deep 
cuts failed to give us the remains of some old saurian,-such as Hadro- 
saurus or Laelaps. Such a discovery would round out the Cretaceous 
most grandly, and might bring us out upon the Jurassic with an 
interest hitherto unknown. 
There have been already obtained in this deposit of Maryland from 
seventy to seventy-five species of fossil shells and casts of shells; but 
no fossil plants except the one noted in this paper. 
We find but little to say upon the Cretaceous of the Virginia shore of 
the Potomac. We found upon examination years ago that the Acquia 
creek sandstone begins below Occoquan Bay, Fairfax county, Va., and 
runs out at Mt. Vernon, and that upon that formation nowhere upon 
the Potomac river could we find any other sign of the Cretaceous, 
except a deposit of very perfect leaves and stems at the White House 
-no black marl, no Cretaceous shells. That fact made the great cliff 
at Fort Washington more incomprehensible. 
If our diagnosis is correct for the lower formation at Fort 
Washington-that it is Jurassic-then by a parity of reasoning that 
formation continues down at least to Smith's Point, Charles county, 
being occasionally lost below high water, and then rising from two to 
six feet above it. 
In the upper end of Charles county, upon the Potomac river, opposite 
Mt. Vernon, there are three thousand acres of land, a plateau from one 
to twenty feet above high tide, surrounded with an amphitheater of 
hills in which Eocene and Cretaceous are well developed. In the plain 
below there is no sign of fossils, neither Miocene, Eocene, nor Cre- 
taceous. 
To what formation then shall we assign this locality? If not Jurassic 
-then, what is it? All the wells of this particular locality penetrate a 
variegated clay but no micaceous sand.-Oliver N. Bryan, Marshall 
Hall, Md. 
Published December 17th, 1889.