THE FOSSILS OF SOUTHWESTERN OHIO
[Photo: View from the southern end of the Schumacker ridge, toward the till-covered hillsides on the southern side of the Kohl branch of Hole’s creek. Till covers the hillsides southwestward as far as Miamisburg.]
93. The Number of Species Found in the Rocks of Southwestern Ohio
The animals whose remains are found in the rocks of southwestern Ohio are all sea animals. No remains of animals living in fresh-water lakes or rivers have been detected in these rocks. Only a few problematic plant remains have been detected and these also are such as belong to marine waters.
The total number of kinds or species know is very great and it is certain that the total number so far discovered forms a small part of the life which in ancient times occupied the seas which at that time covered southwestern Ohio and adjacent areas. Hitherto unknown species are being found frequently within the area here under discussion, and it is certain the total [p. 199] number known will eventually be greatly increased. Moreover, there must have been an enormous number of animals whose bodies did not contain any parts hard enough to resist decay and of whose former existence we can never hope to find any evidence in the form of fossils.
Fully a thousand species of fossil animals are known at present from the blue limestones of southwestern Ohio. Included in this series of rocks are all the strata from the lower part of the Cynthiana group, along the Ohio river, to the top of the Richmond group, just below the quarry level at the Soldiers’ Home, west of Dayton. Of this list of 1,000 species, 400 are known in the Richmond group alone. Since all of this group occurs within the limits of Montgomery county it is certain that diligent search here eventually would result in the discovery of almost all of the species known from the Richmond group. Indeed, Waynesville, a short distance beyond the southeastern corner of the county, is known throughout the world as a great fossil collecting center, on account of the numerous new species discovered in the Richmond strata exposed in its vicinity. This does not mean that more species exist here than elsewhere, but that a large amount of intelligent collecting was done here. The banker Harris, whose magnificent collection now is the pride of the National museum in Washington, devoted the best part of his life to his collection, and made it possible for several other collectors to do the same.
The Brassfield limestone, exposed in the quarries at Soldiers’ Home and at Centerville, formerly was incorrectly identified with the Clinton of New York. From this Brassfield limestone 150 species of fossils have been identified so far. From the overlying Niagaran strata, including in this term all strata from the Dayton limestone, immediately overlying the Brassfield, to the top of the Cedarville limestone, 200 species are known.
94. The Variety of Forms of Life Found Fossil in the Rocks
To adequately represent all of this fossil life would require a large volume. To illustrate none of it would be to omit one of the most interesting details of geological information in our vicinity. To make an adequate selection among so much material presents its difficulties. Hence only two things here are attempted. The first is to give some idea of the diversity [p. 200] of the fossil life formerly in existence. The second is to suggest how rocks from a particular horizon may be identified by illustrating a few of those species whose vertical range appears restricted to definite divisions of rocks and whose presence therefore is regarded as proof of the presence of these divisions.
Corals are represented by figures 6, 8, and 9. Of these the horn coral, Streptelasma rusticum (Fig. 9), is common around Dayton and is often mistaken by the ignorant for small cow’s horns. The honey-comb coral, Columnaria alveata (Fig. 8), is scarce here although common in southern Indiana, near Madison. Forms having the same general appearance, but belonging to an entirely different genus, occur in the Brassfield and overlying limestones. The encrusting coral, Protarea richmondensis, is of interest chiefly because it is found attached to various species of shells in the form of a thin layer. It is common in the vicinity of Dayton.
Crinoids are represented by figure 30. This was an animal which attached itself to the sea bottom by means of a long stem. Its body was covered with small plates and its arms, extending upward, were used to produce currents of water bringing food toward the mouth, which was located at the top of the body, among the arms. Locally crinoids probably were common, but on death the plates, forming that part of the animal which could be preserved as a fossil, usually fell apart so that well preserved specimens of the entire animal are comparatively rare. The specimen figured is called Cupulocrinus polydactylus. Starfish are represented by figure 4, Promopalaeaster speciosus. Only a fragment was found, the missing parts being indicated by the shading. A peculiar form of ancient sea life is represented by figure 1. This is the Agelacrinus pileus, which attached itself to shells and other smooth surfaces. The figure is very much enlarged, the actual specimen being only half an inch in diameter.
Bryozoans are represented by figure 4. Bryzoans of this type are regarded by the ignorant as roots or branches of plants. Careful examination, however, will reveal on the surface of these supposed roots or branches numerous very small pits, each of which formerly was occupied by an individual animal. In other words, the whole organism is made up of a colony of animals originating from a single individual and passing through life [p. 201] inseparable, very much as in the case of the compound coral illustrated by figure 8. The bryozoan here figured is Hallopora nodulosa. Bryozoans often grow to much larger size and not all of them are branched. Some of them grow into flat or nodular shapes.
The peculiar shells known as brachiopods were very common in ancient sea life. They always consist of two separable parts known as valves, and usually they were attached permanently by a short stem or pedicel to some object on the sea-bottom. Usually this pedicel left the interior of the shell by some aperture or notch which can be readily identified, and the valve bearing this aperture or notch is called the pedicel valve, while the opposite valve is called brachial valve. The characteristic feature of these brachiopod shells, by means of which they can be distinguished from other shells, is their bilateral symmetry. In other words, if a line be drawn vertical down the middle of either valve, the parts on the right and left of this line are alike in shape and ornamentation. The following figures illustrate brachiopods: 5, 7, 10, 11, 12, 14, 15, 19, 20, 21, 22, 23, 24, 26, 28, 29, and 31.
The general group of clam shells is represented by figures 18, 25 and 33. As a rule, the two valves are alike in form, but opposite ends of the same valve differ in outline and sometimes also in ornamentation. The shell represented by figure 25 had some of the habits of the modern scallop. It rested flat upon that one of the valves not illustrated here, and this valve became flat and lost its ornamentation. The other valve is seen frequently in the vicinity of Dayton.
Snail shells are represented by figures 13 (Cyclonema humerosum) and 16 (Diaphorostoma trigonostoma). The first species is common along the railroad opposite the Franklin Chautauqua grounds. The second is not rare in the quarries southwest of Springfield.
Orthoceras fosteri (Fig. 27) is a peculiar shell looking like a thick rod, becoming gradually narrower toward one end. Usually only the cast of the interior is found, and this resembles a series of round discs, each disc being curved in a concave direction toward the larger end of the specimen and convex on the other side. These discs represent chambers within the shell. If the entire specimen had been present there would have been evidence of a single, very much longer chamber at the larger end of the speci- [p. 202] men, which formerly was occupied by the animal itself. The series of small chambers probably was useful in making the animal more buoyant while swimming. Its nearest modern representative is the Pearly Nautilus. Even in ancient days some of the related forms of life were coiled as in the Nautilus, but many species were straight, as in the specimen illustrated. The straight forms represent the earlier types of this group of animals. Badly weathered specimens are sometimes mistakes for fossil snakes, and one found in the Soldiers’ Home quarry was labeled for a long time as the backbone of a child. This is no worse than regarding the head and teeth of fossil elephants as remains of giant men, as was done in former centuries, in various parts of Europe, before there was a science of fossils.
Worms, as a rule, present bodies too soft to be preserved in the form of fossils. Nevertheless certain very small black teeth found in some of the rocks of southwestern Ohio have been regarded as the teeth of worms. Figure 24 (Lumbriconereites austini) represents one of these teeth, greatly enlarged, found just beneath the Brassfield limestone north of Wilmington, Ohio. Similar teeth have been found west of the railroad track northeast of Cowlesville, several miles north of Tippecanoe. The specimen here figured was scarcely a tenth of an inch in length.
Trilobites are represented by figures 2, 3 and 17. Calymene retrosa (Fig. 2) is the more common form in the Richmond group near Dayton. In the underlying Maysville strata there is a larger form with more acute corners at the rear lateral angles of the head (Calymene meeki), abundant near Cincinnati. Both forms usually are found rolled up, with the head in contact with the tail, and in this form the fossil formerly was worn as a watch charm. Ceraurus miseneri (Fig. 3) also was found in a rolled-up condition, at Richmond, in Indiana. The species occurs also at the trestle crossed by the Springfield traction road, east of Dayton. Why Calymene niagarensis (Fig. 17) occurs so frequently in the form of spread-out specimens is not known. It is common in the Springfield and Cedarville limestones of southwestern Ohio.
It is evident that these fossils represent quite a considerable variety of life. The complete absence of fish, newts, frogs, reptiles, birds, or ordinary hair-bearing four-footed animals should be noted. No evidence of the [p. 203]
[Photo: View of the watershed area between the south end of the Locust valley farm and the north end of the Kohl branch valley, seen from the south. The line of trees and shrubs at the far left locates approximately the crest of the watershed. The drainage of the field is distinctly indicated, even in the immediate foreground on the left. The far distant hills belong to the Highlands, east of the Locust valley farm.] [pp. 204-5]
[Photo: View of the Walden ridge, taken from the Schumacker ridge, looking westward. An abandoned barn locates the crest of the Walden ridge. A fence at the left of the barn descends the ridge and in the low ground east of the ridge. Note the pebbles in the foreground. On account of the rocks this land is best suited for crops that do not require cultivation. The rains wash away the soil and lighter pebbles, leaving the larger ones exposed.] [pp. 204-5]
existence of any of these occur in the rocks of southwestern Ohio, although the earliest ancestors of fish probably were already in existence elsewhere.
95. Fossils Illustrated on the Accompanying Plates, with an Indication of Their Vertical Range in the Series of Rocks Exposed in Southwestern Ohio
The subdivisions of which the various fossils here illustrated are characteristic, are indicated in the list of species accompanying each plate. The names of these subdivisions are given in consecutive order on page 60.
Of this list, the Eden, Maysville and Richmond groups are included in the Ordovician series of rocks, and the Brassfield, Dayton, Osgood, Springfield, Cedarville and Monroe rocks are included in the Silurian series.
The Columbus and Delaward limestones form part of the Devonian series. Various subdivisions or members of the Eden, Maysville and Richmond groups are recognized by geologists, but are not discussed here.
In descending order, these members are:
Richmond: Elkhorn, Whitewater, Salada, Liberty, Waynesville, Arnheim
Maysville: Mount Auburn, Corryville, Bellevue, Fairmount, Mount Hope
Eden: McMicken, Southgate, Economy, Fulton [p. 206]
[Photo 1: Agelacrinus pileus. Corryville member of Maysville group, at Cincinnati.]
[Photo 2: Calymene retrorsa. Waynesville member of Richmond group. The closely similar
Calymene meeki is common in the Maysville at Cincinnati.]
[Photo 3: Ceraurus miseneri. Whitewater division of Richmond group.]
[Photo 4: Hallopora nodulosa. Upper division of the Eden group, at Cincinnati.]
[Photo 5: Strophomena vetusta. Liberty and Whitewater division of the Richmond group. An
ancestral form occurs in the upper part of the Waynesville division of this group.]
[Photo 6: Protarea richmondensis. From upper Waynesville to top of Whitewater division at
Richmond group. Figure 6B represents this species enlarged.]
[Photo 7: Rhynchotrema dentatum. Arnheim division of Richmond. Closely similar forms occur
in the upper Waynesville and Whitewater divisions.]
[Photo 8: Columnaria alveolata. From upper Waynesville to Whitewater division of Richmond
[Photo 9: Streptelasma rusticum. Waynesville division of Richmond group.] [p. 207]
[Drawing 10: Rafinesquina alternate. From the Trenton to the top of the Richmond group. Within
this range several species should be distinguished.]
[Drawing 11: Hebertella insculpta. A, pedicel valve. B, brachial valve. C, lateral view. D, enlarge
-ment of surface, showing the characteristic transverse sharp ornamenting lines. At base of
Liberty division of Richmond group and also at base of upper third of the Waynesville division.]
[Drawing 12: Rhynchotrema dentatum. Whitewater division of Richmond. Similar forms occur
also in upper Waynesville and at the middle of the Arnheim.]
[Drawing 13: Cyclonema humerosum. Arnheim division of Richmond group, and probably also
in upper part of Maysville group.]
[Drawing 14: Triplesia ortoni. A, brachial valve. B, a fragment of the same valve showing a part
that projects into the interior of the pedicel valve in such a manner as to assist in opening and
closing the shell. C, a similar fragment seen from the side, and often called by children a small
shovel. Brassfield limestone, at Soldiers’ Home and Centerville quarries.]
[Drawing 15: Pentamerus oblongus. Common in the Springfield division of the Silurian lime-
stones. Found also in the Cedarville division. Rare in the Dayton limestone, immediately
overlying the Brassfield limestone.]
[Drawing 16: Diaphorostoma trigonostoma. Upper flat view presented. Seen from the side the
margin is very angular, Cedarville division of Silurian limestones.]
[Drawing 17: Calymene niagarensis. Springfield and Cedarville limestones. The forms of Caly-
mene found in the underlying divisions as far down as the Brassfield limestone usually are
referred to the same species.] [p. 208]
[Drawing 18: Pholadomorpha pholadiformis. Waynesville division of the Richmond group.
[Drawing 19: Rhynchotrema capax. A, the typical form, seen from the side. Whitewater division
of the Richmond. B, less typical form, often compared with Rhynchotrema perlamellosa, found
in the upper Waynesville and in the Liberty divisions.]
[Drawing 20: Strophomena planumbona. A, exterior of brachial valve and top of opposite valve.
B, interior of pedicel valve, Waynesville and Liberty divisions of Richmond group.]
[Drawing 21: Dinorthis carleyi.(often identified as Dinorthis retrorsa). A, interior of pedicel valve.
B, exterior of pedicel valve with top of opposite valve. C, shell seen from the side. Middle of
Arnheim division of Richmond group. A closely similar form occurs at the base of the upper
third of the Waynesville division of the Richmond group.]
[Drawing 22: Plectorthis plicatella. Farimount division of the Maysville group, at Hamilton,
Cincinnati, and elsewhere.]
[Drawing 23: Dinorthis subquadrata. A, brachial valve. B, interior of pedicel valve. C, shell seen
along the hinge line. Liberty and Waynesville divisions of the Richmond group.]
[Drawing 24: Strophomena nutans. A, brachial valve. B, interior of pedicel valve. Upper third of
Waynesville division of Richmond.] [p. 209]
[Drawing 25: Pterinea demissa. Maysville and Richmond group.]
[Drawing 26: Dalmanella jugosa. Waynesville division of Richmond group. Similar forms occur
in the Arnheim division.]
[Drawing 27: Orthoceras fosteri. Waynesville division of the Richmond group.]
[Drawing 28: Orthorhynchula linneyi. Cynthiana group, chiefly in Kentucky. Here this species
occurs also in the upper part of the Fairmount division of the Maysville group.]
[Drawing 29: Platystrophia acutilirata. Whitewater division of the Richmond group. Similar forms
occur in the Liberty division.]
[Drawing 30: Cupulocrinus polydactus. Liberty division of Richmond group.]
[Drawing 31: Platystrophia ponderosa. A, view along the hinge line. B, pedicel valve. From
upper part of Fairmount to top of Mount Auburn division of Maysville group, also near middle
of Arnheim division of the Richmond group.]
[Drawing 32: Promopalaeaster speciosus. Probably Fairmount division of Maysville group at
[Drawing 33: Byssonychia radiata. Waynesville division of the Richmond group. The typical
forms of Byssonychia radiate occur in New York state, in the Lorraine group.]
[Drawing 34: Lumbriconereites austini. Single tooth, one tenth of an inch in length, here greatly
magnified. Elkhorn division at the top of the Richmond group.] [p.210]