In addition to lithic raw materials available in Minnesota, this list includes selected nonlocal raw materials occasionally found at archaeological sites in the state. In general, more complete information is provided on the locally occurring materials.
If a material is know by more than one name, alternate names are cross referenced to a preferred name. The correlations of multiple names to a single material are based on a careful reading of published information, and on information provided informally by other archaeologists. The correlations given here are conservative. Please remember, however, that some of these names may be used by some authors more broadly than this list implies. In addition, many reports use names that relate to a descriptive category rather than a specific material (e.g., "blue-black, mottled chert") . Unless such a name has become well established as referring to a specific raw material, it is not included in this list.
The materials listed under the heading See Also are usually materials which have similar characteristics or which are related in origin. In the course of conducting a raw material analysis, special attention should be paid to these materials in order to avoid misidentifications.
The stated Distribution is based on published information, personal observations by the author and information provided by colleagues. Distributions are deliberately stated in broad, regional terms. More specific information may be available from the sources listed under Main References. These references include, when possible, the first definitive citations on a given raw material, subsequent works which include important descriptive or distributional information, or the most complete citations available. In some cases, when such sources are especially difficult to procure, more accessible works have been substituted. These alternate citations general refer back to any earlier, definitive works.
The Quarry Sites (including procurement sites which are not quarries in the strictest sense) listed also include sites in adjacent states and provinces. This is in part because quarry sites are not common, and very few have actually been found in the state; to discuss any significant number of quarry sites requires inclusion of quarry sites outside the geopolitical limits of Minnesota. Quarry sites outside the state are also mentioned because they feasibly could, and probably in many cases did, serve as sources of raw material for the inhabitants of what is now Minnesota.
Diagnostic Features are given in some cases. These are not intended to be complete characterizations, but rather to give a few hints on distinctive characteristics useful in identifying a material and distinguishing it from similar materials.
|Agate||See Lake Superior Agate
Although a variety of "agates" are found in neighboring areas, Lake Superior Agate appears to be the only agate occurring in Minnesota. Romano (1991) notes that Gunflint Silica has occasionally been misidentified as Moss Agate at archaeological sites in Minnesota. The term "Moss Agate" is better applied to a different material of more westerly origin.
|Agatized Wood||See silicified wood|
|Algal Chert||This name occurs in the geological literature. It is not clear what materials are covered by the term, or whether they constitute a usable resource. Steinbring (1974:68-70) postulates that "a very homogenous light brown chalcedony" from Pickerel Lake and other northern Minnesota sites may originate in "Pre-Cambrian algal domes in the vicinity of Schreiber, Ontario, northeast of Thunder Bay." However, examination of artifacts from some of the northern Minnesota sites (at the Wilford Archaeology Laboratory, University of Minnesota, Minneapolis) suggests that the material discussed by Steinbring may be light colored Hudson Bay Lowland Chert.|
|See Also:||Hixton Quartzite|
|Distribution:||Western Wisconsin, possibly restricted areas of southeastern Minnesota|
|Geologic Context:||Cambrian, top of the Jackson (?) Sandstone (R. Bozhardt, personal communication 1994)|
|Main References:||Morrow & Behm 1985:13; Penman 1981:7-8|
|Quarries:||Synstad, 47BF63 (Penman 1981:7-8)|
|Diagnostic Features:||Although Alma Quartzite and Hixton Quartzite are similar in some respects, Alma may be distinguished by its larger grain size and poorer cementing of grains (Penman 1981:7).|
|Animikie Silicates||See Gunflint Silica, Jasper Taconite and Kakabeka Chert
This term covers the above named materials, and possibly other related raw materials, which originate in the Animikie Group. The Animikie Group includes geological formations occurring in northeast Minnesota and adjacent areas. It appears that all of the Animikie Silicates share certain characteristics, such as a transparent, chalcedonous matrix. Many of these materials also share a distinctive, "icy" texture.
|Arenaceous Chert||See Tongue River Silica|
By strict geological definition, argillite and siltstone are different materials. The differences, however, are subtle and of little concern for most archaeological applications. Although both names are commonly used by archaeologists, the term "siltstone" is given preference here because it is more obviously descriptive.
|Baked Shale||See porcellanite|
|Bijou Hills Quartzite||See Bijou Hills Silicified Sediment|
|Bijou Hills Silicified Sediment|
|Other Names:||Bijou Hills Quartzite, Ogallala Orthoquartzite
Church (1994) recommends using the name "Ogallala Orthoquartzite" for BHSS and related materials occurring in Nebraska. However, given that the "Bijou Hills" name is well established, and that Ogallala Orthoquartzite is more broadly defined, the previous name is retained here. Ogallala Orthoquartzite is still a useful term, and may gain widespread usage.
"Ogallala Orthoquartzite" should not be confused with Ogallala Chert, a material found in parts of Texas and Oklahoma (Hughes 1955:55).
|Distribution:||South central South Dakota, north central South Dakota; Anderson (1980:200) notes that "small quantities are present in northwest Iowa gravels," suggesting that glacial and fluvial distribution is more widespread.|
|Geological Context:||Pliocene/Miocene, Bijou facies of the Valentine and Ash Hollow formations; possibly Cretaceous age Fox Hills or Hell Creek formations|
|Main References:||Ahler 1977:137-138; Church 1994; Porter 1962:268-269|
|Diagnostic Features:||A fairly distinctive greenish grey to light green color, combined with a granular quartzite structure.|
|Biwabik Silica||See Gunflint Silica
Romano (1994) has recently proposed the existence of a variety of metamorphically altered Gunflint Silica, which he calls Biwabik Silica. Further information on that material is not provided here, pending additional examination of raw material specimens and consideration of archaeological distribution.
|Brown Chalcedony||See Knife River Flint; cf. Cedar Valley Chert, chalcedony, silicified wood
It seems that most references to "brown chalcedony" at sites in and around Minnesota actually refer to Knife River Flint. This may be a holdover from the cautious tone of earlier researchers, who apparently did not feel they had enough information about KRF (and other regional materials) to be confident in the identification of that material. It may also result in part from some lingering doubt over the distribution of KRF, and a reluctance to imply origin from the KRF primary source area by plainly calling a material "Knife River Flint." However, at this time KRF is probably the most intensively studied and best documented material in the region and its distribution is fairly well known; samples are widely available and identification can be made with a high degree of confidence. Thus the use of the name "Knife River Flint" is preferable in most instances. It is possible that, occasionally, in some reports "brown chalcedony" refers to other materials. For example, there are vague but persistent references to a "light brown chalcedony" or "gold chalcedony" occurring in northeastern Minnesota. This material is discussed in further detail under Hudson Bay Lowland Chert.
|Distribution:||Southeastern Iowa, western Illinois, eastern Missouri|
|Geologic Context:||Middle Mississippian, Burlington Limestone|
|Main References:||Ives 1975, 1984; Meyers 1970:11, 12; Morrow 1983, 1984:101-102; Rick 1978 (especially for heat treatment); Withrow 1983:54-56|
|Diagnostic Features:||Quite variable, difficult to characterize succinctly. Commonly fine textured, high quality, white or near white. Also often has a reddish cast, less often purple. Fossils common, often abundant. Tends to have a noticeable reddish cast to transmitted light.|
|May Resemble:||In the Western Resource Region, may occasionally be confused with Red River Chert. In the Southern Resource Region, may occasionally be confused with Prairie du Chien Chert, or with various cherts originating in northern Iowa.|
|Cathead Chert||See Red River Chert
The terms "Cathead Chert" and "Red River Chert" are not precisely synonymous. The latter is a broader category, and includes another material known as "Selkirk Chert." If Cathead or Selkirk cherts can specifically be identified, it is probably preferable to use these more specific names. This is the usual practice in Manitoba, where both cherts occur in outcrops. In Minnesota, however, these materials are mixed in the drift. Because their characteristics (and distribution) overlap, the broader term "Red River Chert" was coined (Bakken 1985) to cover these materials when drift derivation made it hard to separate them.
|Cedar Valley Chert|
|Other Names:||Cedar Valley Jasperoid, Root River Chert, Solon Chert; probably Cochrane Chert
The original definition of this material (Ready 1981) concentrated on the opaque variety, which was called "Cedar Valley Jasperoid." The translucent varieties were mentioned only briefly. When other investigators began to take note of the translucent varieties, it was initially proposed that they be called "Solon Chert," because they were believed to be derived from the Solon Member of the Cedar Valley Formation. Later, Gonsior (1992) proposed renaming both varieties "Cedar Valley Chert," and distinguishing two varieties: opaque ("jasperoid") and translucent. That usage is followed here.
The term "Root River Chert" is also used for this material, principally by archaeologists working in southwestern Wisconsin. In a few reports, the term "Cedar Valley Chert" may refer to the material otherwise known as Grand Meadow Chert. (See the discussion under Grand Meadow Chert.) A careful reading should clarify the usage.
Archaeologist working in southwestern Wisconsin have identified a material called "Cochrane Chert" (Robert Bozhardt, personal communication 1994) which appears to be indistinguishable from the opaque variety of CVC.
|Distribution:||Southeastern Minnesota, possibly southwestern Wisconsin. The distribution of this material is not well documented.|
|Geologic Context:||Devonian, Wapsipinicon Group, Spillville Formation|
|Main References:||Gonsior 1992; Ready 1981|
|Quarries:||Hadland, 21FL60 (Ready 1981); Chally/Turbenson (21FL71) (Gonsior et al. 1993)|
|Diagnostic Features:||There are two varieties of Cedar Valley Chert, opaque and translucent, with little or no overlap apparent between the varieties. The opaque variety corresponds to the gold brown to brown, homogenous and highly opaque material which has elsewhere been identified as "Cedar Valley Jasperoid." Heat treatment produces a rich and distinctive, deep red color, and may produce a waxy or almost glassy texture. Otherwise, the texture is generally chalky. Normally homogeneous in appearance, but may be somewhat mottled. The range of characteristics of this material is limited.
The translucent variety shows much greater variation, even within individual cobbles. Color ranges from golden brown to pale brown, yellow, white and colorless. Patterning varies from homogenous to mottle. Macroscopic appearance varies from slightly to moderately translucent and cherty, to translucent or (rarely) transparent and chalcedonous. Many pieces even have an appearance which strongly resembles quartzite. Microscopic examination, however, reveals that the material does not actually contain grains and is not a quartzite. In the translucent variety, transmitted light will be golden yellow in all but the more translucent, colorless pieces.
|May Resemble:||Translucent variety may superficially resemble Hixton Quartzite or other quartzites, or Knife River Flint.|
|Cedar Valley Jasperoid||See Cedar Valley Chert|
|See Also:||Cedar Valley Chert, Hudson Bay Lowland Chert, Knife River Flint, silicified wood|
|Distribution:||Small pieces of chalcedony appear to be widespread, although not common, in glacial drift in many parts of the state. Their ultimate origin is not clear.|
|Diagnostic Features:||Translucent to transparent. Very fine grained, homogeneous. Often has a waxy texture.|
|Cochrane Chert||See Cedar Valley Chert The term "Cochrane Chert" has been used by some Wisconsin archaeologists to describe a material first noted near the town of Cochrane in west central Wisconsin, near the Mississippi River. This material appears to be a variety of what is here described as the opaque variety of Cedar Valley Chert, although the Wisconsin material has a more waxy or glassy texture and a more distinctive grainy color patterning. Geologically, the presence of this material in this part of Wisconsin is difficult to explain, and it may ultimately prove to be a different material (Robert Bozhardt, personal communication 1994).|
|Drusy Quartzite||See Swan River Chert|
|Felsite||See siltstone The term "felsite" is not synonymous with siltstone. This usage was based on an initial misidentification of the material at certain sites in northwestern Ontario. This usage is probably limited to archaeological reports for this region during a restricted period of time (cf. Fox 1980:136).|
|Fired Brick||See porcellanite|
|Fossilized Wood||See silicified wood|
|Other Names:||Nehawka Flint, rice grain chert. Names for specific varieties of Fusulinid Chert include Argentine, Bethany Falls, Hertha, Plattsmouth, Spring Branch and Winterset cherts.
"Fusulinid Chert" is a category of cherts rather than a single chert type. The name may still be useful in some situations, however, such as at Minnesota sites where it occurs only rarely and in small amounts. In such a situation, more specific identification is not always practical. Morrow (1994) provides a useful key for identifying specific varieties of Fusulinid Chert.
|Distribution:||Southwest Iowa, northwest Missouri, parts of eastern Nebraska and Kansas|
|Main References:||Logan 1988; Morrow 1994; Reid 1980, 1981, 1984|
|Diagnostic Features:||Variable. A good key for several varieties of Fusulinid Chert is provided by Morrow (1994). Often dark in color with light colored fossils. Fossils often have a "rice grain" appearance.|
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