The reason amateurs make such a significant contribution is simply that there are so many more of them than professionals. It is often true, as well, that many amateurs spend more hours in the field and search with greater enthusiasm than many professionals, who are often preoccupied with curatorial and administrative duties. Not surprisingly, some of the most important soldiers in the ranks of the amateurs are children. They tend to have more free time and will investigate locations adults might not. Anyone can make a contribution!

The primary difficulty faced by the amateur is lack of information. How do you know where to look? How do you know if what's been found is important? And what do you do if you have a find of uncertain importance?

The following outline is intended to guide the amateur through these and other questions.

WHERE TO LOOK

Before you can decide where to look, you must first decide what it is you are looking for. In almost every case, fossils are found in sedimentary rocks (i.e., water-laid, layered rock). Therefore, the most important questions are the age of the rocks and whether they were deposited under marine or fluvial conditions. This information can be found on geologic maps. (See Map Sources, p. 32.)

As has already been noted, dinosaurs were land dwellers that lived during the Mesozoic Era, from about 245 to 66 million years ago. You should, therefore, look for rocks deposited by rivers during that time period. In Maryland, this includes the Triassic rocks (Newark Group) of the Gettysburg and Culpeper Basins, found in Montgomery, Frederick, and Carroll Counties, and the Lower Cretaceous clays (Potomac Group), which form a wide northeast-southwest band that passes through the cities of Baltimore and Washington. Because of their close proximity to the ancient shoreline, dinosaur bones have also been found in the marine deposits of the Upper Cretaceous Severn Formation.

The Triassic basins are part of a much larger Triassic-Jurassic rift system extending from Nova Scotia to the Carolinas. The sedimentary rocks of these basins are a mixture of sandstones and shales, ranging in color from red to black. The red shales and sandstones occasionally contain dinosaur and other tracks, with sporadic white to reddish bones. The bones in these beds are often difficult to see. When looking for tracks, it is generally best to look for interbedded shales and sandstones, because tracks are best preserved as impressions in mud infilled and cast by the overlying sand. The black and gray layers are the remains of ponds. In places they contain large amounts of organic materials like plants and fish skeletons. Occasionally, a dinosaur, reptile, amphibian or their tracks are preserved in one of these ponds. When a creature is preserved in pond sediments, it is often complete. Bones found in such deposits tend to be black in color.

The Lower Cretaceous Potomac Group, like the rocks in the Newark Group, is part of a much larger system that stretches from Nova Scotia to Georgia. It consists of clays, sand, and gravel, with sporadic sedimentary iron ore. Although few living persons have found dinosaur bones in situ in the Potomac Group, there are historical descriptions of the stratigraphic position of the bones. A typical account follows

Muirkirk and Contee. Tyson was the first to direct attention to animal remains in the Potomac Formation, and the observations which he placed on record in 1860 have been amply confirmed by the results of recent work___with a single exception: no cetacean or other mammalian fossils have lately been seen. It seems probable that Tyson mistook some of the huge dinosaurian bones occasionally found in the section to which he refers, for bones of whales; an error which might easily occur.

In 1887 collections were made by Marsh from one of the mines of the Muirkirk region, under the auspices of the United States Geological Survey, resulting in the discovery of 'a new genus of Sauropods, and other new Dinosaurs.'

During the summer of 1894 the writer's attention was directed to additional saurian fossils which had been found in the same mine explored by Marsh, and at various other points apparently yet unexplored. Several of these new localities were examined with some care in the hope both of adding to our knowledge of the species already known and of the discovery of additional forms. Though the work was attended by much difficulty, a considerable collection was obtained in a comparatively short time.

The fossils have been placed in the hands of Professor Frederic A. Lucas, of the United States National Museum for study.

The collection comprises:

It also includes a number of forms yet undetermined.

Among the more interesting fossils of the collection may be mentioned a tibia, probably of Allosaurus, which measures ten inches in width, and thirty-two inches in length, exclusive of the ends, which are lacking. In the same beds ("brown charcoal clay") and at about the same level, were found fragments of other bones of similar dimensions, and a tooth . . . probably belonging to the same individual. Half a mile distant in a bed of similar character a single vertebra was found which is probably referable to the same species.

Among the rarest fossils of the collection is the tooth of Astrodon (johnstoni Leidy?). Tyson discovered the first two specimens of this tooth near Bladensburg, about 1859. Dr. Christopher Johnston made sections of one of them for microscopical study, and very briefly refers to them in a Note upon Odontology as the teeth of "Astrodon," a name which he coined descriptive of the appearance of the dentine in cross section. They were subsequently described by Dr. Leidy, who named the reptile Astrodon johnstoni in honor of Dr. Johnston. These teeth, with the one lately obtained . . . constitute the only known vestiges of this Dinosaur.

The character of the deposits about Muirkirk and Contee which contain the plant and animal remains has already been described.

The section is briefly as follows:

The deposits of animal remains occurring in the vicinity of Muirkirk and Contee are mostly in the divide between the Patuxent and Potomac depressions, and are from a hundred to two hundred and sixty feet above sea level. The circumstance that they are considerably more abundant toward the upper limit, and pretty closely associated (vertically) with the remains of Cycads suggests that these reptiles were most abundant about the time of the maximum Potomac submergence, which the presence of the Cycads would indicate to have probably been attended by the warm climate suited to animals of this class.
    Patuxent. Near Patuxent, Anne Arundel County, on the estate of Mr. L. Welsh, three fragments of another huge (silicified) tibia were recently found. A fossil cycadean trunk, and considerable silicified coniferous wood have also been found on the surface of the same estate and hillslope.
    Jessup. About 1886 a large femur (?) was taken from the iron mine of Dr. A.S. Linthicum of Jessup. This was given to the U.S. Geological Survey. Vertebrate remains have also been seen in the mines of the State House of Correction, near Jessup.
    Hanover. The next point northward where they have been both reported and found is in the mines bordering the Deep Run depression, near Hanover. A large limb bone was found a few years since at a considerable depth, in one of the mines of Mr. P.R. Wilson, and Mr. C. Van Buren Smith of Wellham's Cross-roads has a silicified fragment of a huge dinosaurian tibia which appears to have come from this neighborhood.
The unusual abundance of silicified cycadean and coniferous vegetation in the valley of Deep Run has already been noticed.
    Baltimore. During the past winter while making collections of plant remains from the shafts at Covington and Ostend streets, an impression was seen much resembling in outline and dimensions the track of a single toe of a Brontozoum-like Dinosaur. It occurred in the fossiliferous "slaty clay" near the plant bed. It was carefully removed, but being fragile, was destroyed in transportation.
     Stemmer's Run. Vertebrate remains have lately been reported in the vicinity of Stemmer's Run. Independent of these rumors the character of the deposits north-east of Baltimore is such as leads us to expect to find in that section fossil remains, both vegetable and animal, similar to those occurring between Baltimore and Washington. (From Johns Hopkins University Circular No. 121, Notes on the Paleontology of the Potomac Formation, by Arthur Bibbins, Oct. 1895)
    There is a good deal of confusion about the Potomac Group finds. Although all of the dinosaur fossils have traditionally been ascribed to the Arundel Clay, the middle formation of the Group, there are those geologists who insist that the tripartite division of the Potomac Group has no validity. To be sure, dark-gray clay lenses are found in all three formations___Patuxent, Arundel, and Patapsco. The bones, which range from brown to red to black in color, are said to be found in these iron-bearing clays.

     In addition, important plant fossil finds have been made in all formations, including cycad and bennettitales trunks in the Patuxent-Arundel and early angiosperms in the Patapsco

The Severn Formation belongs to a belt of marine deposits that extend from Long Island to Alabama and up the Mississippi Valley. The fauna of the Severn Formation is almost exclusively marine, but because the Severn was deposited in the nearshore, especially in the parts of Prince George's County nearest Washington, D.C., occasional dinosaur bones have been found as washed-in elements. Marine reptiles like mosasaurs, plesiosaurs, crocodiles, and turtles are, of course, much more common.

When wet or fresh, the sediments appear black; when dry they are light gray. The sediments are mostly unconsolidated, but there are some moderate to large calcareous concretions which have abundant, though jumbled, fossil faunas. Because the teeth and bones are black, they are all but invisible in the fresh sediments. When the sediments have been washed by rains for a time, the bones and teeth become more apparent by their shiny or polished appearance.

WHAT'S IMPORTANT

As a rule, any bone or tooth found in these formations should be considered important, especially if you are unfamiliar with the fauna. Bones and teeth, except for shark and fish teeth which tend to be flattened rather than conical like reptilian teeth, are generally rare to extremely rare in these formations.

WHAT TO DO WITH YOUR FIND

The hardest decision for most amateurs is what to do with a find. No one has any right to take it from you, not even a museum. However, permission should always be secured before collecting on any property but your own.

Despite the ownership of the fossil by the finder, it is desirable that scientifically important specimens be donated to museums. As a matter of policy, museums do not buy specimens. Why, then, should you donate your specimens to a museum? Museums live forever; people do not. The first sauropod tooth found in North America at Bladensburg, Maryland, can still be studied and seen by anyone needing to do so in the Peabody Museum at Yale University, more than 135 years after its discovery.

The museum will not take all your fossils. Less than 10 percent of what is brought to the museum is important enough to be kept. What an amateur considers spectacular or valuable may not be important to a museum. A 5-inch shark tooth is an exciting find, but the museum may have its drawers full of even larger specimens. A small scrap of bone or tooth that is almost invisible may represent the presence of an entirely new group of animals in a fauna. Only the experts can tell you! But even the experts depend on you to provide some information, such as the location of your discovery. Knowing where the fossil was found is often very helpful, if not necessary, in identifying the specimen.

Local places to take finds follow: