A.&M. College of Texas, College Station
Amarillo College, Amarillo
Arlington State College, Arlington
Austin College, Sherman
Baylor University, Waco
Blinn College, Brenham
Corpus Christi, University of, Corpus Christi
Del Mar College, Corpus Christi
East Texas State College, Commerce
Hardin-Simmons University, Abilene
Henderson County Junior College, Athens
Houston, University of, Houston
Howard County Junior College, Big Spring
Kilgore College, Kilgore
Lamar State College of Technology, Beaumont
Lee College, Baytown
McMurry College, Abilene
Midwestern University, Wichita Falls
North Texas State College, Denton
Odessa College, Odessa
Pan American College, Edinburg
Rice University, Houston
St. Mary’s University, San Antonio
San Angelo College, San Angelo
San Antonio College, San Antonio
Southern Methodist University, Dallas
South Texas College, Houston
Southwestern University, Georgetown
Stephen F. Austin State College, Nacogdoches
Sul Ross State College, Alpine
Tarleton State College, Stephenville
Texarkana College, Texarkana
Texas Christian University, Fort Worth
Texas College, Tyler
Texas College of Arts and Industries, Kingsville
Texas Technological College, Lubbock
Texas Western College, El Paso
The University of Texas, Austin
Trinity University, San Antonio
Tyler Junior College, Tyler
West Texas State College, Canyon
[Illustration: Plate 6
Fossil Identification Chart
I RADIAL SYMMETRY]
A. Tapering, cylindrical cone-shaped fossils
1. Cone-shaped with longitudinal partitions or septa
Coral
2. Fossils with septa or sutures; tapering at one end
Cephalopod
3. Shell without internal partitions or sutures
a. Shell large heavy, external longitudinal ribs. Cretaceous only
Rudistid
b. Shell small, tusk-shaped open at both ends. Rare in Paleozoic
and Mesozoic
Scaphopod
B. Disc or dome-shaped fossils
1. Star pattern on top
Echinoid
2. Subconical small pits or pores on top
Bryozoan
3. Small disc-shaped (less than ½ inch)
Orbitoid Foraminifera
4. Disc-shaped or button-like, with longitudinal partitions or septa
Coral
C. Fossils composed of segments or plates
1. Circular discs or chambers; when united form cylinder
a. Tapered shell
Cephalopod
b. Not tapered, segments small of uniform thickness, hole in
center
Crinoid Stem
2. Fossil composed of many-sided plates
a. Bud-shaped, 13 wedge-shaped plates
Blastoid
b. Cup-shaped, many curved plates branching arms
Crinoid
[Illustration: Plate 7
Fossil Identification Chart
II BILATERAL SYMMETRY]
A. Fossil coiled in a single plane
1. Shell divided by internal transverse partitions or sutures
Cephalopod
2. Shell without internal partitions or sutures
Gastropod
3. Shell small, spindle-shaped; resembles wheat grain. Pennsylvanian
and Permian
Foraminifera fusulinid
B. Fossil not coiled
1. Shells or valves similar to clams
a. Plane of symmetry parallel to hinge; equivalved
Pelecypod
b. Plane of symmetry almost at right angles to hinge; strongly
ribbed; “Scallop-like” with “ears”, inequivalved
Pelecypod
c. Plane of symmetry at right angles to hinge-line; without
“ears”, not “Scallop-like”; commonly with opening in beak,
inequivalved
Brachiopod
2. Fossil tapering, cylindrical or cone-shaped
a. Cone-shaped, internal longitudinal partitions or septa
Coral
b. Tapered, internal transverse partitions
Cephalopod
c. Shell without internal septa or partitions
(1.) Shell large heavy, longitudinal ribs. Cretaceous only
Rudistid
(2.) Shell small, tusk-shaped, open at both ends, rare in
Paleozoic and Mesozoic rocks
Scaphopod
3. Fossil heart-shaped, domed or flattened; star pattern on top
Echinoid
4. Fossil segmented
a. Divided into 3 lobes, may be curled up. Paleozoic only
Trilobite
b. Flattened or elongate, resembles shrimp
Crustacean
[Illustration: Plate 8
Fossil Identification Chart
III NO APPARENT SYMMETRY]
A. Shell without transverse partitions or sutures
1. Shell coiled like ram’s horn, low spired; shell has two valves,
smaller flattened valve often missing. In Texas exclusively
Cretaceous
Pelecypod
2. Shell tightly coiled, most have higher spire than 1, shell
smaller and not as rough as 1, has only one valve
Gastropod
B. Coiled fossils, coiling not in one plane
1. Shell with transverse internal partitions or sutures
a. Partitions always smooth, thick shelled, loosely and
irregularly coiled, in Texas exclusively Cretaceous
Caprinid
b. Partitions (sutures) generally wrinkled, regularly and tightly
coiled
Cephalopod
2. Shell without transverse internal partitions or sutures
Gastropod
3. Solid spiral ridge around central axis, resembles corkscrew
Bryozoan
C. Uncoiled fossils
1. Fossil resembles narrow saw blade. Paleozoic only
Graptolite
2. Fossil irregularly cone-shaped, longitudinal partitions or septa
Coral
3. Shell resembles clam or oyster, nonsymmetrical
Pelecypod (mostly oysters)
4. Branching twig-like fossils
a. Covered with minute pores or openings
Bryozoa
b. With evenly distributed larger openings with septa
Colonial coral
5. Lace-like fossils, occur as thin sheets or films
Bryozoa
6. Masses of circular or polygonal tubes with septa
Colonial coral
7. Irregular fossils, cylindrical with rough surface
a. Large axial opening with thick wall, external longitudinal
ribs. Cretaceous only
Rudistid
b. Solid, no opening, small pits or pores. Pennsylvanian or
Permian
Sponge