![](file:///C|/Documents%20and%20Settings/aashworth/My%20Documents/web/courses/g491/glacial_potholet.jpg) |
Fossil
pothole at Taylors Falls, Minnesota. Formed by meltwater from Glacial
Lake Duluth. Downcutting exposed Late PreCambrian basalts . Mike Rudolph
for scale. |
![](file:///C|/Documents%20and%20Settings/aashworth/My%20Documents/web/courses/g491/glacial_pothole3t.jpg) |
Fossil
pothole at Taylors Falls about 25 feet deep eroded into Proterozoic basalt
|
![](vesicular_massive_basalt2T.jpg) |
Contact
between massive and vesicular texture in a basaltic lava flow. Aric Olsen
for scale |
![](2003images/thumbnails/vesicular_basaltt.jpg) |
Vesicular
basaltic lava |
![](pahoehoeT.jpg) |
Pahoehoe
texture (1.1 Ga) |
![](file:///C|/Documents%20and%20Settings/aashworth/My%20Documents/web/courses/g491/amygdulest.jpg) |
Amygduloidal
basalt |
![](file:///C|/Documents%20and%20Settings/aashworth/My%20Documents/web/courses/g491/cambrian_conglomerate2t.jpg) |
Millstreet
Conglomerate, Ironton Formation, Franconian Stage, Taylors Fall, Minnesota |
![](2003images/thumbnails/cambrian_cobblet.jpg) |
Crushed
shells of inarticulate brachiopods attached to a boulder from the Cambrian
conglomerate at Taylors Falls |
![](cambrian_precambrian_unconf.gif) |
St.
Croixian Series (Upper Cambrian) sandstone unconformably overlies basalts
of the Chengwatana Group (Late Proterozoic). Reuben Panchol for scale. |
![](curtain_fallsT.gif) |
Franconian-aged
(Upper Cambrian) sandstone at Curtain Falls, nr Taylors Falls, Minnesota.
Aric Olsen for scale. |
![](inarticulates2T.jpg) |
St.
Croixian Series inarticulate brachiopods from St. Croix Falls, Wisconsin |
![](2003images/thumbnails/cambrian_trilobite.jpg) |
Pygidium
of the Upper Cambrian trilobite Uncaspis from the Eau Claire Formation,
Willow River , Wisconsin |
![](hyolithidT.jpg) |
Hyolithus
from the
Eau Claire Formation, Willow River , Wisconsin |
![](ripplemarks_tracefossilsT.jpg) |
Trace
fossils and ripple marks (crests are orange-brown) from the St. Lawrence
Formation, Red Wing, Minnesoata |
![](trace_fossils2T.jpg) |
Detail
of trace fossils from the Upper Cambrian St. Lawrence Formation, Red Wing,
Minnesota |
![](chad_weisenburgerT.gif) |
Red
Wing fault - St. Lawrence Formation (yellow) against the Franconia Formation
(green - glauconitic). Chad Weisenburger for scale. |
![](ord_brachsT.jpg) |
Slab
of limestone covered in mostly orthid brachiopods from the Middle Ordovician
Decorah Formation , Spring Grove, Minnesota |
![](trilobiteT.jpg) |
Small
Isotelus from the Maquoketa Formation, Upper Ordovician, nr. Granger,
Minnesota . Specimen
collected by Mike Wright. |
![](bumastusT.gif) |
Bumastoides?
from the Galena Group limestones, near Greenleafton, Minnesota. Specimen
collected by A.C.A. about 15 years ago. |
![](isotelus_acaT.jpg) |
Isotelus
from a Decorah Formation limstone, Spring Grove, Minnesota. Specimen collected
by A.C.A. 10 years ago |
|
|
![](galena_trilobiteT.jpg) |
Trilobite
(Ceraurus?) embedded in a Stewartville Formation limestone, Greenleafton,
Minnesota.
|
![](diplograptusT.jpg) |
Diplograptus
from the Middle Ordovician Galena Group limestones, near Greenleafton, Minnesota |
![](orthoconic_nautiloidT.jpg) |
Orthoconic
nautiloid from the Platteville Limestone, near Spring Grove, Minnesota.
Specimen collected by Jeff Suttle about 10 years ago (see scale for size) |
![](orthoconic_nautiloid2T.jpg) |
Section
of an orthoconic nautiloid from the Platteville Formation, Middle Ordovician.,
near Spring Grovr, Minnesota |
![](macluritesT.jpg) |
Maclurites
from the Middle Ordovician Galena Group limestones, near Wyckoff, Minnesota |
![](receptaculid3T.jpg) |
Fischerites
- a receptaculid from the Middle Ordovician Galena Group limestones, near
Greenleafton, Minnesota - surface view. |
![](receptaculidT.jpg) |
Fischerites
- a receptaculid from the Middle Ordovician Galena Group limestones, near
Greenleafton, Minnesota - side view. |
![](discontinuityT.jpg) |
Discontinuity
in a Prosser Formation limestone (Galena Group), near Greenleafton, Minnesota
|
![](strom_biostrome2T.jpg) |
Contact between the Lithograph
City Formation and the lower stromatoporoid biostrome of the Shell Rock
Formation. Upper Devonian limestones from Mason City , Iowa. Justin Costa-Rica
for scale. |
![](strom2T.jpg) |
Banded
stromatoporoid from the Upper Devonian Shell Rock Formation, Mason City,
Iowa. |
![](styolite2T.jpg) |
Styolites from the Upper Devonian Lithograph
City Formation, Mason City, Iowa |
![](students_workingT.jpg) |
A
working group of NDSU students |
![](ReubenT.gif) |
A
Reuben based on Reuben Panchol - an alternative to the English and metric
systems? |
![](roark_franklundT.jpg) |
Roark
Franklund - wet feet and all collecting in the Willow River |
![](g303wrgroupT.jpg) |
Team
A - Willow River State Park |
![](g303groupwr2T.jpg) |
Team
B - Willow River State Park |
![](g303group_stpeterT.jpg) |
Paleo
Field Trip group 2003 on a St. Peters Sandstone outcrop. |
![](geobuttsT.jpg) |
Geology
303 butts. |
![](g303group_2003T.jpg) |
Paleo
Field Trip group in Rockford, Iowa. |
![](ashworth_rockford_T.gif) |
Allan
Ashworth |