984 THE PALEONTOLOGY OF MINNESOTA. 



[Lophosplra perforata. 



concave above the lower carina; upper slope moderately concave in the outer 

 part; umbilicus very small, sometimes apparently covered by the reflected inner 

 lip. Surface with transverse and revolving lines, the former curving strongly 

 backward toward the peripheral band and consisting of two sets, one lamellar 

 with distant raised edges, the others exceedingly fine, parallel with the other 

 set, and five or six times as numerous. The whole surface, including the 

 peripheral band, is covered with the revolving lines which are inclined to be 

 irregular and more delicate even than the transverse set, requiring a good light and 

 a magnifying power of no less than four diameters to be clearly visible. On the 

 peripheral band the lunulae are distant and strongly curved backward. 



Differs from the earlier L. spironema in having the basal part of the last turn 

 slightly more ventricose, the carinse less strong, the peripheral band rounded instead 

 of sharp, and the surface markings more delicate excepting the sublamellose growth 

 lines which are wanting in that shell. L. pulchella also resembles it greatly but has 

 a smaller apical angle and so far as observed its surface is entirely without 

 revolving lines. 



The extreme delicacy of the surface markings renders them unusually liable to 

 removal through maceration and weathering. The best examples were obtained^ by 

 picking away the thin parasitic bryozoan, Leptotrypa clavis Ulrich, which frequently 

 covers this and other fossils of the Utica group. Without the characteristic surface 

 ornamentation L. tenuistriata might be confounded with the young shells of the 

 Utica form of L. oweni. In such cases, however, the presence of a lower carina in 

 the tenuistriata and its absence in the oweni will usually suffice in distinguishing them. 



We have before us two imperfect specimens, collected by one of the authors in 

 the Stones River group at High Bridge, Kentucky, of another species of Lophospira 

 with spiral lines. It is larger than either of the two of this type described in this 

 work, and differs from them besides in having the revolving lines coarser and in 

 wanting the lower carina. The general shape and character of the shell seems to 

 have been very similar to our L. medialis. 







Formation and locality. Shales of tbe Utica group, Cincinnati, Ohio, and Newport and Covington, 

 Kentucky. 



Collection. E. O. Ulrich. 



LOPHOSPIRA PERFORA.TA, n. sp. 



I'l.ATi: I.XXIIT, FIGS. 32-35. 



Murchisonia bicinctaf MEEK and WOUTHEN, 1868, Geol. Sur. 111., vol. iii, p. 317, pi. in, flg. 4. (Not 

 M. licincta HALL, 1847.) 



Hight 33 mm.; greatest width 26 mm.; apical angle about 50. Volutions six 

 or seven, relatively depressed, with the bight and width, as shown in a transverse 



