...I. E. Odom Abstract The Upper Cambrian (St. Croixan Series) in the northern portion of the upper Mississippi Valley consists primarily of sandstone with minor amounts of shale and carbonate. This paper presents data on the relation of the mineralogy of the sandstones, particularly feldspar content...

... or in combinations, will insure uniformly reliable results under all circumstances. Criteria whose worth has been proved for . . . 1 Published by permission of the Director of the U. S. Geological Survey. The terms Ozarkian, Canadian, St. Croixan, and some details of classifications as used in this paper have...

... Beekmantown group Prairie Du Chien formation Shakopee dolomite New Richmond sandstone Oneota dolomite CAMBRIAN St. Croixan group Jordan sandstone St. Lawrence limestone Franconia sandstone HURONIAN (ALGONKIAN) Sioux quartzite Of these formations...

...) formations. The St. Charles (Croixan) formation in the original Blacksmith Fork section is redefined, as the upper 827 feet contain Ordovician fossils. The name Tatow limestone is applied to the youngest Waucobian rocks in the House Range. The upper 370 feet of the original Pioche shale in the Highland Range...

...C. A NELSON Abstract In the Upper Mississippi Valley Croixan strata above the Franconia formation consist of dolomite and dolomitic siltstone and sandstone overlain by massive nondolomitic sandstone. Previous classifications of this succession have employed both faunal and lithologic criteria...

.... The fashion of proposing new period names then inaugurated was especially prevalent the next 6 or 8 years and resulted in the proposal of Tennesseean, Waverlyan, Cincinnatian, Canadian, Ozarkian, Waucoban, Acadian, St. Croixan, and perhaps others as coordinates of Cambrian, Devonian, Jurassic, et cetera...

...W. H. Twenhofel Cambrian .—The Cambrian strata consist of sandstones and sandy shales which include one or two members of sandy dolomite. They belong to the St. Croixan or Upper Cambrian, the upper limit of which is taken as the base of the Lower Magnesian dolomites. The total thickness...

... Megagroup of Cambrian and Ordovician age is in part contemporaneous with the Potsdam and extends from the base of the St. Peter Sandstone down only to the base of the Potosi Dolomite in northern Illinois but to the base of the Bonneterre Dolomite in southwestern Illinois. The Ottawa Limestone Megagroup...

... Valley deposition. The Johns Valley boulders were derived from stratigraphic units of both the Arbuckle and Ozark facies of the foreland province, as well as from units indigenous to the frontal and central Ouachita Mountain provinces. Boulders range in age from Late Cambrian (Croixan) through...

... in the quartzite from which oil is produced probably originated as a system of joints resulting from prolonged subaerial weathering of quartzite monadnocks on the pre-St. Croixan peneplain and/or on the early Pennsylvanian land surface on which they were re-exposed. These quartzites have not been subjected...

... sandstone and micaceous shale more than 2,000 feet thick separates the Freda Formation (generally considered to be uppermost Keweenawan) from the overlying St. Croixan Series. In Michigan these rocks are known as the Jacobsville Sandstone and crop out along the southern shore of Lake Superior from the tip...

... . Cambrian trilobites from the St. Croix Valley . Journal of Paleontology , 25 : 765 – 784 . Nelson , C. A. 1956 . Upper Croixan stratigraphy . Geological Society of America Bulletin , 67 : 165 – 184 . Owen , D. D. 1852 . Report of the geological survey of Wisconsin, Iowa...

...NIGEL C. HUGHES; GERALD O. GUNDERSON; MICHAEL J. WEEDON Abstract Several localities within the heterolithic facies of the St. Lawrence Formation (Upper Cambrian) of Wisconsin and Minnesota yield specimens with phosphatic exoskeletons, quadrate cross sections composed of four equidimensional faces...

... Prairie du Chien Gp B Ordovician Canadian Prairie du Chien Gp   Cambrian St. Croixan Jordan Ss, Eminence Fm, Potosi Dol, Franconia Fm A Cambrian St. Croixan Ironton Ss, Galesville Ss, Eau Claire Fm, Mt. Simon Ss * Abbreviations: Dol = dolomite, Fm = formation, Gp = group, Sgp...

... Society of America Bulletin , 106 . 492 – 506 . Runkel , A.C. , 1994b , Revised stratigraphic nomenclature for the Upper Cambrian (St. Croixan) Jordan Sandstone, southeastern Minnesota : Minnesota Geological Survey Report of Investigations , 43 . 60 – 71 . Runkel , A.C. , Miller...

.... , Berg , R.R. , and Nelson , C.A. , 1956 , Croixan type area, Upper Mississippi Valley , : in Rogers , J. , ed., El sistema Cambrico, su paleogeografia y el problema de su base, Tomo II, Parte II : Australia, America : XX Congreso Geologico Internacional, Mexico , p. 415 – 446...

... SILURIAN NIAGARAN E ALEXANDRIAN 438 z 12 Ma CINCINNATIAN L ORDOVlCIAN CHAMPLAINIAN E CANADIAN 505 *- 7~2 Me / LI ST. CROIXAN CAMBRIAN [ Saginaw Grand Rapids Traverse Detroit River Bayport Michigan Marshall Coldwater Shale Sunbury Shale Berea Ss. EIIsworth Sh. Bedford Sh Antrim Shale Undivided in subsurface...

... these mountains were sufficiently reduced to be overlapped by the St. Croixan series in southern Wisconsin and there are relatively few breaks in the sequence of later sediments which covered the area. As these beds are practically horizontal, we may infer that the locality has not been appreciably disturbed...

... borehole geophysical logs and outcrops. For example, natural gammaray logs from closely spaced boreholes penetrating the nearshore and proximal offshore shelf facies of the Jordan Sandstone and underlying St. Lawrence Formation in the Twin Cities metropolitan area (Fig. 9) delimit seaward-shingled...

...Paul A. Catacosinos Abstract The composite Cambrian sequence of the Lower Peninsula of Michigan consists, in ascending order, of the Mt. Simon Sandstone; Munising Group, composed of the Eau Claire Formation, Galesville Sandstone, and Franconia Formation; St. Lawrence Formation; Lodi Formation...