. The Geology of Minnesota . and are frequently some- *Zeitschr. der deutsoh. geolog. Gesellsch., vol, .\-xxii., p. 559, pi. 33, 1S80. 716 THE PALEONTOLOGY OF MINNESOTA. [Illajnus indeterminatus. what abraded and in rather an unfavorable condition for study. An enrolledspecimen from Kenyon retains the parts better than any other observed. Formation and locality.—lUcenus americanus, like I. crassieauda, has a very restricted verticalrange, though of distinctly later date than the latter. Billings spealcs of it as a rare species occurring inthe Trenton limestone only, at Ottawa, LOrignal, and la
. The Geology of Minnesota . and are frequently some- *Zeitschr. der deutsoh. geolog. Gesellsch., vol, .\-xxii., p. 559, pi. 33, 1S80. 716 THE PALEONTOLOGY OF MINNESOTA. [Illajnus indeterminatus. what abraded and in rather an unfavorable condition for study. An enrolledspecimen from Kenyon retains the parts better than any other observed. Formation and locality.—lUcenus americanus, like I. crassieauda, has a very restricted verticalrange, though of distinctly later date than the latter. Billings spealcs of it as a rare species occurring inthe Trenton limestone only, at Ottawa, LOrignal, and lake Huron. In the Trenton limestone ofTrenton Falls it is not uncommon and is exquisitely preserved. In Minnesota it is kncvpn only in theGalena limestone and shales at Wykoff, Kenyon, Old Concord, Cannon Falls, and in Goodhue county;also at Oshkosh, Wisconsin, and Galena, Illinois. iLLiENus; compare I. indeterminatus Walcott. Illcenus indeterminatus Walcott, 1879. Thirty-first Ann. Rept. N. Y. State Mus. Nat. Hist., p. Fig. 24.—Cranidium of IlloiHus; cf. /. indeterminatus Walcott. There is a single cranidium of comparatively large size, from the lower Trentonbeds at Janesville, Wisconsin (Museum No. 8413), which agrees very well with thedescription given by Walcott, and is characterized by the conspicuous developmentof the dorsal furrows, which clearly define the lateral outline of the glabella. original specimens were from Herkimer county, N. Y. (Black River lime-stone), and from Plattesville, Wisconsin. Subgenus THALEOPS, Conrad, 1843. Thaleops ovata Conrad, 1843. Thaleops ovata Conrad, 1843. Proc. Acad. Nat. Sci. Phil., vol. i, p. .332. Thaleops (Illcenus) ovatus Hall. 1843. Pakuontology of New York, vol. i, p. 259; pi. 67. flgs. 6a, ovatus Whitfield, 1882. Geology of Wisconsin, vol. iv, p. 238; pi. 5, flgs. herricki Foerste, 1887. Fifteenth Ann. Rept. Geol. and Nat. Hist. Surv. Minnesota, , flg. 2. This appears to be the mos
Size: 1856px × 1346px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookidgeologyofmin, bookyear1897
