576 THE GEOLOGY OF MINNESOTA. 



[Cretaceous bads. 



" The same kind of greenish marl is exposed up the Waraju, the immediate bluffs being 

 somewhat wrought in it, to a point just back of New Ulm, where the bank is opened by Mr. Win- 

 kelmann for laying pipes to supply his machinery and brick-yard. The trench which he has dug 

 passes through it just before reaching the bank of the Waraju river." 



In a later examination of the strata at Mr. Winkelmann's, Prof. Winchell has noted 

 about 40 feet of the green shale, with thin layers of concretionary limestone; underlain by red 

 shale, of which a thickness of about 5 feet was seen, but it may extend below the river-level, which 

 is some five feet lower than the base of the section exposed. Occasional layers of red shale were 

 seen somewhat above its general mass, separated from it by green shale. There seems to be a 

 very slight dip toward the south. 



Prof. James Hall, in the paper referred to on page 98, mentions ferruginous sandstone, con- 

 taining plant remains, interbedded with red marls, lying below the green shale and concretionary 

 limestone in the vicinity of Mr. Winkelmaim's limekiln. Four species of fossil leaves, collected in 

 these beds by Hall, and found also in other states on the west and south, are described by Lesque- 

 reux, who regards them as proof that the formation belongs to the Dakota group at the base of the 

 Cretaceous series.* The green shale and nodular limestone may belong to a later formation, and 

 Prof. Winchell refers them provisionally to the Niobrara group. The highest divisons of the 

 Cretaceous series seem also to be represented in these counties, at least by fossils derived from 

 them, found in the drift as noted in the description of wells in Milford and Stately. 



Of the Cretaceous strata seen at New Ulm Prof. Winchell writes: "The flat on which New 

 Ulm stands seems to be made up by a terrace wrought in the Cretaceous. The surface of this 



flat is strewn with boulders The general section of the Cretaceous at New Ulm is 



as follows: 



1. Drift, gravel and boulders, with a surface-loam in some places, or large- 



ly made up of sand 10 to 20 ft. 



2. Fine clay, blue, bedded, weathering white, used for pottery or brick 4 to 10 ft. 



3. Sand or fine gravel, not cemented, readily crumbling, containing mag- 



nesian balls, or rounded lumps made up of a fine white powder seen 20 to 30 ft. 



"The conspicuous Cretaceous terrace that occurs along the Minnesota at New Ulm, is due 

 to this fine sand, overlain by a more tenacious clay or shale. The varying composition of the 

 Cretaceous makes it difficult to establish the horizontality of different outcrops, but there cannot 

 be much doubt that No. 3 above is the equivalent of No. 2 of the section on the Waraju." The 

 section here referred to has been presented on page 574, its No. 2 being white sand, 100 feet 

 thick, overlying the deposits that are dug for making fire-bricks. 



The terrace at New Ulm thus formed of Cretaceous beds, overlain by drift, is more than a 

 mile long, parallel with the river, and varies in width from twenty-five to fifty rods or more. 

 Minnesota street, the principal business avenue, is on this terrace, sections of which, agreeing 

 well with that just quoted, are exposed, especially near its south end, by ravines and gullies at its 

 margin. Its night is about 90 feet above the bottomland and river, and 40 feet above the depot, 

 which is on an intermediate terrace. The west part of New Ulm, including State street, several 

 churches and the county buildings, occupies a higher terrace or plateau of modified drift, which is 

 elevated some 25 to 35 feet above Minnesota street, or 115 to 125 feet, approximately, above the 

 river (see fig. 47, page 582). Further details respecting the topography and geology of the Min- 

 nesota valley in this vicinity will be brought out in treating of the glacial and modified drift. 



FIG. 46. SECTION ON THIKD NORTH STREET, NEW ULM. 



In the north part of New Ulm the grading of Third North street close northeast of the rail- 

 road, exposes Cretaceous clays. This cut (fig. 46) is 14 feet deep and 200 feet long, with its top 

 about 45 feet above the river. Its upper 4 feet are soil and drift, containing and overspread with 



*U. S. geol. survey of the territories; vol. vi, The Crelacioun Flora, pp. 6. 68, 76, 90 and 93. These species are Ficus 

 (f) HaUiana, Lesq., Laurophyllwn reticulatum, Lesq., Bumelia Marcouana, Ijean^Leguminosites J/arcouanus, Heer) and 

 Lirioaendron Meekii, Heer. The last two are figured in Dana's Manual. 



