Maryland's Official State Fossil Shell

As of October 1, 1994, the official fossil shell of Maryland is an extinct snail, or gastropod: Ecphora gardnerae gardnerae Wilson. Actually, this same fossil snail was first designated by the Maryland General Assembly in 1984, but there has been a name change. The legislature's action in 1994 was in response to a name change by the scientific community. The previous name was Ecphora quadricostata (Say). Changes in nomenclature are nothing new for Ecphora (or for most fossils, for that matter).

This fossil snail was one of the first fossils from the New World to be illustrated in a scientific work in Europe. It has been reported that a rather poor drawing of an Ecphora first appeared in William Huddesford's printing of the third edition of Martin Lister's "Historiae Conchyliorum" (or History of Conchs) in 1770 in England. It was labeled "a marilandia," or "from Maryland." (Contrary to what has appeared in print at least are far back as 1904, this fossil was not the first from North America to be so illustrated. That honor likely falls to a fossil clam, now known as Chesapecten jeffersonius, which appeared in Lister's own first edition in 1687.)

The shells of the various species and subspecies of the genus Ecphora constitute one of the most unusual and diagnostic types of fossil in the Miocene fauna of the mid-Atlantic region. Key characteristics that aid in identification by collectors are

1. a russet color, which contrasts with the more common white color of most other mollusks;
2. four strongly protruding "ribs," or costae, which are T-shaped in cross section; and
3. its moderately wide umbilicus, which is a hollow cone-shaped feature along the axis of coiling (Fig. 1).

You might wonder why the names of fossils are sometimes changed. And why do fossils have such "odd" names? Proposing names and changing names are not whimsical. Paleontologists have shown that there were differences between the Ecphora quadricostata from the upper part of the St. Marys Formation (Miocene age) of Maryland and the Ecphora quadricostata from the lower Pliocene strata of tidewater Virginia. Since the species designation E. quadricostata had first been assigned to the fossil from Virginia (thus giving its name priority), the scientific name of the Miocene gastropod from Maryland had to be changed. The honor of naming a fossil falls to the paleontologist who first publishes the revised classification and nomenclature. In this case, that was Druid Wilson, who was working for the Smithsonian Institution at the time. In 1987, he proposed the name Ecphora gardnerae. Soon after that, two other paleontologists (Ward and Gilinski, 1988) further subdivided the genus Ecphora, and introduced several subspecies. Thus was born the name of Ecphora gardnerae gardnerae Wilson for the distinctive fossil shell. (Strictly speaking, from a taxonomy and nomenclature viewpoint, "Wilson" is part of the complete name and should not be in parentheses.) There are other species and subspecies of Ecphora in the Miocene strata of Southern Maryland, and they each have their own distinguishing characteristics.

The name of the genus often, but not always, is derived from a Latin or Greek word that is descriptive of some key characteristic of the organism. The second part of the name identifies the species and also derives from Latin or Greek. The species name may reflect some characteristic feature of the organism, or refer to the locality where it was first found, or may be a "latinized" word in honor of some noted paleontologist. For example, the Maryland fossil shell derives its genus name from the Greek ekphora, meaning "protruding." The species name, quadricostata, comes from the Latin for "four ribs" (quad = four; costa = rib)., in reference to the presence of four strongly developed protruding "ribs," or costae. (Note that the T-shape distinguishes this fossil from other related four-ribbed species of Ecphora.) The more recent species designation of gardnerae is in honor of U.S. Geological Survey paleontologist Julia Gardner (Wilson, 1987). In this case, the subspecies name is a repetition of the species name, and the name "Wilson" denotes the person who originated the species name.

The various species of Ecphora are fairly common in the Miocene strata of Maryland. Ecphora inhabited the waters of an earlier stage of the Atlantic continental shelf, areas now occupied by Chesapeake Bay and parts of Southern Maryland and Eastern Shore. There are several collecting localities for the various species of Ecphora in Maryland, and they include all three of Maryland's Miocene formations - from oldest to youngest, the Calvert, the Choptank and the St. Marys Formations. To the amateur collector, it is fairly easy to confuse the various species of Ecphora. The most detailed descriptions and photographs appear in Ward and Gilinsky (1988).

In Maryland, Ecphora gardnerae gardnerae Wilson occurs in the St. Marys Formation. Ward and Gilinsky (1988) noted that this fossil species is common in a particular portion of the formation, informally called the “Windmill Point unit”. This informal subunit apparently corresponds to some of the youngest sediments of the formation. Reportedly a good exposure of the St. Marys Formation occurs on the right bank of the St. Marys River about a mile upstream of Windmill Point. Chancellor Point (mentioned below) is located on the left (east) bank of the river less than a mile upstream of Windmill Point.

The best specimens of Ecphora are reported from the renowned Calvert Cliffs north of Little Cove Point, Calvert County, and from Chancellor Point, St. Marys River, St. Mary's County. Both locales are in the St. Marys Formation. However, these and most other locales are on private property. All would-be collectors must receive permission from the landowner to hunt fossils on privately owned land. At Calvert Cliffs State Park in Calvert County, collecting is allowed along a small section of beach, but is not permitted along the cliffs due to landslide hazard. Although the State Park is rich in many Miocene fossils, it is a poor site for collecting specimens of Ecphora.

Contact our publications office for the interactive BULLETIN 20: Miocene Fossils of Maryland on CD-ROM

Selected References:

Germon, R. N., Ward, L. W., and Ray, C. E., 1988, Ecphora -- important fossil from the Miocene strata on the Chesapeake Bay: The Maryland Naturalist, 31(1): 25-33.

Petuch, E. J., 1988, New species of Ecphora and Ecphorine Thaidids from the Miocene of Chesapeake Bay, Maryland, U.S.A.: Bulletin of Paleomalacology, 1(1): 1-16.

Ward, L.W., 1993, Evolution of a name, or what species of Ecphora is that again? American Paleontologist, Paleontological Research Institution, Ithaca, NY, 1(2): 1-2.

Ward, L.W. and Blackwelder, B.W., 1975, Chesapecten, a new genus of Pectinidae (Mollusca: Bilvalvia) from the Miocene and Pliocene of eastern North America: U.S. Geological Survey Professional Paper 861, 24 p.

Ward, L. W. and Gilinsky, N. L., 1988, Ecphora (Gastropoda: Muricidae) from the Chesapeake Group of Maryland and Virginia: Notulae Naturae, Academy of Natural Sciences of Philadelphia, No. 469, 21 p.

Wilson, D., 1987, Species of Ecphora in the Pungo River Formation, in C. E. Ray (ed.), Geology and paleontology of the Lee Creek Mine, North Carolina, II: Smithsonian Contributions to Paleobiology, 61:21-29.

Compiled by the Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218
February, 1993; revised July, 1994

Compiled by Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218
This electronic version of "Fact Sheet No.6 " was prepared by R.D. Conkwright, Division of Coastal and Estuarine Geology, Maryland Geological Survey.