Mineral Resources On-Line Spatial Data
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Geologic units in Ramsey county, Minnesota
- Middle Ordovician rocks, undivided (Middle Ordovician) at surface, covers 53 % of this area
Middle Ordovician rocks, undivided - Decorah Shale; limestone of the Platteville Formation; shaly rocks of the Glenwood Formation; and St. Peter Sandstone in the Hollandale embayment of southeastern Minnesota
- Lower Ordovician rocks, undivided (Lower Ordovician) at surface, covers 28 % of this area
Lower Ordovician rocks, undivided - Shakopee and Oneota Formations of the Prairie du Chien Group in the Hollandale embayment of southeastern Minnesota. Unit consists dominantly of dolostone and dolomitic limestone. The Shakopee also contains intervals of quartz arenite, including a pronounced basal unit named the New Richmond Member
- Upper Cambrian, undivided (Late Cambrian) at surface, covers 5 % of this area
Upper Cambrian, undivided - Jordan Sandstone; dolomite, glauconite, and silty glauconite rocks of the St. Lawerence and Franconia Formation; Ironton and Galesville Sandstones; sandy and shaly rocks of the Eau Claire Formation; and the Mt. Simon Sandstone.
- Decorah Shale (Middle Ordovician) (Middle Ordovician) at surface, covers 14 % of this area
Decorah Shale (Middle Ordovician) - Light-greenish-gray shale and lesser amounts of coquinoid limestone, especially in the upper half of the formation. Mapped as a separate unit where possible.