1897.] NEW YORK ACADEMY OF SCIENCES. 277 



Summation of the evidence. 



From the foregoing table it will be seen that of the thirty spe- 

 cies recognized in the Batesville Sandstone fauna, ten point 

 to the St. Louis age of the formation, six to its Kaskaskia age, 

 and fourteen species are present whose evidence is indeterminate. 

 After setting aside the fourteen species that afford no evidence, 

 and considering the relative number of species alone, it is seen 

 that Q2^fc of the evidence points toward the St. Louis age and 

 Sl^fo toward the Kaskaskia age of the formation. 



In making a just estimate of the evidence of the age of the 

 fauna, however, it is necessar}- to take into account not onl}' the 

 relative number of species, but also the relative abundance of 

 the species. The most abundant species of the fauna, Produc- 

 tus cestriensis^i is characteristicalh' a Kaskaskia form, and of the 

 six Kaskaskia species only one is marked (r.) and one (rr.), four 

 being common or abundant forms. Of the St. Louis species 

 four only are common, three are marked (rr.) and three (r.). From 

 this it will be seen that when only the abundant or common spe- 

 cies are considered, the evidence of the age of the formation lies 

 equall}' between the St. Louis and the Kaskaskia. 



From a consideration of the paleontologic evidence alone, 

 without an}' reference to the stratigraphy, the Batesville Sand- 

 stone should be correlated with the base of the Kaskaskia group. 

 The presence of the numerous Kaskaskia species establishes the 

 Kaskaskia age of the fauna, while the association with them of 

 the numerous species typically belonging to the St. Louis group, 

 fixes its horizon in the basal portion of the Kaskaskia. 



Relation between the farinas of the Batesville Sandstone and the 

 Maxville Limestone. 



The Maxville Limestone is a formation in Ohio, about twenty- 

 five feet in thickness, and lies immediately above the Logan 

 group, the uppermost subdivision of the Waverly series. Its 

 fauna has been made known b}' Whitfield.* It consists of a 

 mingling of St. Louis and Kaskaskia species, and the limestone 

 is spoken of by Prof. Whitfield as " the equivalent of the 

 St. Louis and Chester f Limestones of the Mississippi Valley." 

 Such a thin stratum can scarcely be considered as representing 

 the whole of the great thickness of the St. Louis and Kaskaskia 

 groups as developed in the Mississippi Yalle}-, and it has been 



♦ Ann. N. Y. Acad. Sci., Vol. .5, pp. .576-595, and Geol. Surv. Ohio, Vol. 7, pp 465-481. 

 t The names Chester and Kaskaskia are synonomous, Kaskaskia being the earliest 

 of the two referred to the formations. 



