Boone County, Arkansas, United States, North America
Accession Date:
30 Aug 2012
Collection Date:
1970 to 1990
Notes:
OJC-1: Ordovician Jefferson City, Variety 1, Quartzite. A light to medium gray ground features darker gray splotches and bands. Medium sized silica or quartz grains are well cemented in a very light gray to off-white silica. Bands are formed by the presence of a greater number of silica grains in a zone than elsewhere. Fracture caused by knapping goes both through and around the grains. This is a dense stone. The workability is fair, 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.
