1022 THE PALEONTOLOGY OF MINNESOTA. 



LSolenosplra prlsca. 



been changed because the first had been used previously under Murchisonia, The 

 next American species occur in the St. Louis group of the Subcarboniferous system, 

 from which Hall has described three species, M. attenuate/,, M. turritella and M. 

 vermicula, every known character of which allies them with Solenospira. Of Euro- 

 pean species probably belonging here, we may mention the Devonian M. tricincta 

 d'Arch. and Vern., and the Carboniferous M. quadricarinata McCoy, M. larcomi 

 McCoy, M. gracilis Goldf., and M. nana and M. tenuis of DeKoninck. There are some 

 new species also, and no doubt others have been described, but it is difficult to 

 decide from illustrations alone whether they belong here or not. Some of the latter 

 having more than four revolving carinse may belong to Aclisina. 



SOLENOSPIRA PRISCA Billings. 



PLATE LXX. PIGS. 52-55. 



Eunema prisca BILLINGS, 1859, Can. Nat. and Geol., vol. iv, p. 360. 



Murchisonia (Eunema f) pagoda WHITFIELD, 1883, Geol. of Wis., vol. iv, p. 218. (Not Eunema f pagoda 

 SALTEK.) 



We have eight more or less imperfect specimens, three of them casts, the rest testiferous, one from 

 Minneapolis, two from Wisconsin, three from Dixon, Illinois, and two from Murfreesboro, Tennessee, of 

 a species of this genus, that after repeated efforts we have failed to distinguish from the Calciferous shell 

 which Billings called Eunema prisca. In all these specimens, the largest indicating a total length of 

 between 40 and 50 mm., the apical angle is constantly about 14. Our figures 53 and 55 (Plate LXX) are 

 so clear and satisfactory that a detailed description is unnecessary. Besides these we have another lot of 

 seven specimens that is not exactly like the first lot. The specimens of the second lot, namely, while 

 agreeing precisely with the northwestern form as far down the spire as the eighth or tenth whorl, from 

 here on reduce the apical angle to only about 10. At the same time the relative hightof the whorls is 

 increased. These peculiarities are shown very well in figures 52 and 54. If a subordinate name is desired 

 for this peculiar Tennessee form, it may be called var. extenuata. 



Compared with S. pagoda Salter sp., the only difference of any consequence is that while each whorl 

 in that shell has four carinas two in the middle, one below and one above, the latter two being almost in 

 contact at the suture S. prisca has but three, the upper one being absent, while the lower one is visible 

 on the base of the last whorl only. 



Formation and locality. Billings' types came from the "Calciferous sandrock, Mingan Islands." The 

 specimens used by us are all from the Stones River group at the localities mentioned above. 



Collection. E. O. Ulrich. 



SOLENOSPIRA PAGODA Salter. 



PLATE LXX, FIGS. 56-80. 



Eunemaf pagoda SALTER, 1859, Canadian Organic Remains, Dec. 1. p. 30, pi. vn, fig. 5. 

 Not Murchisonia (Eunemaf} pagoda WHITFIELD, 1883, Geology of Wisconsin, vol. iv, p. 218. ( Soleno- 

 spira prisca BILLINGS sp.) 



Hight generally 25 to 30 mm., probably not exceeding 40 mm. ; apical angle 14 or 16 ; volutions ten 

 to fifteen, furnished each with two prominent keels which divide the surface into three approximately 

 equal concave spaces or furrows ; a third but smaller carina above at the sutural edge, while a fourth is 

 visible generally only on the base of the body whorl; surface markings, aside from the strong revolving 

 keels, consisting of extremely fine lines of growth which are directed rather strongly backward from both 



