Mountain Home, Arkansas, United States, North America
Accession Date:
30 Aug 2012
Collection Date:
1970 to 1990
Notes:
OJCU-3 (Ordovician Jefferson City-Cotter Undifferentiated, Variety 3): Found in the Mountain Home area of Arkansas. A dark gray field features medium gray streaks and occasional light gray splotches. This forms one part of the stone while the other part is a dark or medium gray quartzite. Texture of the dolomite ranges from fine to medium, while that of the quartzite varies from coarse to medium. Knappability is fair to poor (rarely good).
JEFFERSON CITY. The Jefferson City formation is found on the surface throughout the southern half of Missouri, except in the extreme southeast and in the western counties (except McDonald & Barry, where limited amounts occurr). Over much of this area the Jefferson City and Cotter are not differentiated because the lithiologies are similar and often thin. In many cases the mottled and irregularly banded Jefferson City dolomite cannot be separated from from similarly marked Cotter. A careful microscopic examination reveals few distinguishing differences, so these are best left undifferentiated. The following two varieties seem to be clearly associated with the Jefferson City formation.