a tour of devonian fossils
TRANSCRIPT
A Do-It-Yourselves Tour in 23 Slides
If you lived here, you’d be near the equator!
Another View....
Fossil site
Rochester
Genesee River
All Devonian: limestone, shale, sandstone
Note: Yellow shows Silurian....Rochester is mostly Silurian – not as old...
The Devonian Sea
Tops of Horn Corals... they rarely fossilize
Most likely Fossil finds at Little Beard’s CreekHorn Corals, Brachiopods, Trilobites, Crinoids,Pelecypods
Horn Corals
All horn corals became extinctduring the Great PermianExtinction
Crinoids “Sea Lillies” and Trilobites (on the surface). Large Arthropod is a Eurypterid...we will not find fossil samples here, but they are the New York State Fossil!
Calyx “flowerish top” israrely found, but stem piecesare common...and very small
Crinoids are Alive today, but not nearly as common as in the past.
Bryozoans....Colonial animals...live in connected colonies, very tine asindividuals...can be seen in stem-like connected fossils...Thousandsof species of them live today.
Brachiopods...the most commonlyfound fossils at L.B.Creek
Palm size and much smaller...
Look like Clams, but are not relatedName means Shoulder-Foot
They have a foot that extends intothe sea bottom and anchors them.
Some are ‘winged’, some round. All are Symmetrical on the surface, BUT thetop and bottom shells are different sizes. Bottom
Top
Brachiopods became extinct during one of the Three Devonian Extinctions
The 3 Major Devonian Extinctions
Pelecypods...common in the Devoniancommon now...include clams!
Note the top of the shells are NOTSymmetrical!
NOTE We will not find them at Little Beard’s Creek, but the first Tetrapods...land animals that evolved from Lobe-finned fish evolved. Tetrapods are believed to be a link between Lobe-finned fish and Amphibians.
Last minute notes: wear shoes that can get wet...have dry ones for lunch and the return to school.
Be sure and bring a labeled bag for fossils...an old sock is good for small ones!
If you have a rock hammer, do bring it but also a pair of googles! The science department has several
hammers. Bring enough goggles for the # of hammers. Rock hammers are not necessary. Nail
hammers are not safe for use on rocks!!!