168 JURASSIC PERIOD. 



examples, this volution has a revolving rounded prominence, situated a little 

 nearer the suture than the base, which causes a more or less conspicuous 

 flattening of the outer side of the volution, as well as a slighter flattening 

 of the space between that prominence and the sutm-e. All the examples of 

 this species in the collection having been preserved in a hard arenaceous 

 lunestone, all the characters of the inner lip could not be ascertained. 



Surface marked by moderately distinct lines of growth, and sometimes 

 faint indications of revolving striaj are also seen. 



Greatest diameter of the largest example in the collection, thirteen 

 millimeters ; shorter diameter, ten millimeters ; greatest height, lying with 

 its aperture downward upon the table, eight millimeters. 



While preparing the preliminary report {he. cit), I thought I had 

 ascertained to a good degree the character of the inner lip, but subsequent 

 examination still leaves the true character of it in doubt. 



Position and locality. — Strata of the Jnrassic period ; Salt Creek, near 

 Nephi, Utah, where it is associated with Pentacrinus asteriscus Meek and 

 Hayden. 



