DESCRIPTIONS OF SPECIES. 305 



1897. Eumetrin rerneuilana. Weller, New York Acad. Sci., Trans. , vol. 16, p. ^■'iQ. (Date of volume 

 1898. ) 



Batesville sandstone: Batesville, Ark. 

 1899. Eumetria ■vemeuiliana. Girty, U. S. Geol. Surv., Mon., vol. 32, pt. 2, p. 560, pi. 68, fio;.«. 12a-126. 



Madison limestone: Yellowstone National Park. 



Ju.st as ill the higher beds of the Mississippian series in the Mississippi Valley 

 two specie.s of Eumetria were early recognized, one a large form with coarse striae, 

 the other smaller and with finer ornamentation, so in the material from Colorado a 

 similar condition is found to exist, and although it has been general of late to unite 

 Ev. vera and Eu. vermeuilixma into one species. I feel indisposed to follow a similar 

 course in treating the specimens under discussion. 



The coarsely striated form from Colorado has been accordingly referred to Eume- 

 tria woostiTi. The finely striated one I have distinguished from it under the name 

 Eumetria marcyi. In so doing and in adopting here the common synonymy of that 

 species which includes the names Eumetria cerneuiliana (which my specimens espe- 

 cially resemble) and Eumetria vera (to which Eu. woosterl is closel}' allied), I am 

 aware that my course is not altogether consistent, l)ut I am hopeful at least that the 

 distinctions which originally led to the proposal of these specific names will be found 

 significant of differences of geologic age, or geographic occurrence. I have not at 

 hand, however, the fossils and stratigraphic data upon which to establish an opinion 

 or rest a proof of the validity and relationship of Eumetria altiroatrin^ Eumetria vera, 

 Eumetria verneiiiliana, Eumetria marcyi, and Eumetria woosteri, and their synonymy, 

 and hardly venture to di-sturb the status quo by an invalid attempt at betterment. 



The smaller variety has so far lieen found in Colorado onlj' in the San Juan 

 region. It is a comiDai'atively rare form, and the specimens collected are so frag- 

 mentary that only general comparisons are possible. 



The largest specimen has a length, probably, of not more than 12 mm., and has 

 at the margin 8 or 9 stria; in the space of 5 mm. These fossils, as far as I am able 

 to judge, agree very clo.sely with examples of the same size from Spergen Hill, 

 Indiana, representing Ev. vemeuiliana, although a larger series of more perfect 

 specimens may show that the Colorado form should not be referred to Hail's species. 



As the fauna with which this form occurs in Colorado is with little doubt of 

 Osage age, the range of Eu. verr\,euiliana is somewhat increased in a downward 

 direction by this identification. Yet since at least one representative of the genus 

 {Eu. altirostris) is known in the Kinderhook, it is much more a matter for surprise 

 that the line of de.scent should have been interrupted by the apparent absence of 

 Eiimetria from the Osage of the Mississippi Valley, than that it should have come 

 to light in the Osage faunas of the Rocky Mountain region. 



This .seems to be the form which in the Madison limestone of Yellowstone Park 

 I cited under the same specific name, Ewmetria verneuilAana. It differs considerably 

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