CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD 



89 



Rimella Aeassiz 



Rim ell a 



Figure 



Description.— Shell of moderate size, rather broadly fusiform; number of 

 whorls known five; sculpture on last volution consisting only of about fifteen 

 delicate, spiral striae revolving around the basal half of the whorl which is else- 

 where entirely smooth; sculpture on penultimate whorl consisting of one strong 

 medial spiral thread and a few rather irregular, more or less obsolete, longitudinal 

 riblets, better developed on the earlier half of the whorl; sculpture on third whorl 

 consisting also of one medial revolving spiral and a number of close-set longitudi- 

 nal riblets or plications; the latter also form the ornamentation of the fourth and 

 fifth volutions; each whorl has one or more rather inconspicuous varices. 



Length of incomplete shell 21, greatest width 10 mm. 



Remarks.— This is the first Rimella found in the Lower Eocene. None has 

 before been discovered in either the Midway or Lignitic horizons of southeastern 

 North America or northeastern South America. 



The writer takes great pleasure in naming this shell in honor of Mr. William 

 Fowler, of Guanoco, Venezuela, whose many kindnesses did so much to render 

 pleasant her visit to Venezuela. 



Locality.— Bed No. 8, Soldado Rock, Gulf of Paria. 



Geological horizon. — Lignitic Eocene. 



Rimella knapp 



Figu 



Description.— Shell of moderate size, slender, subfusiform, with a high, very 

 acute and tapering spire; whorls nine or ten; spiral sculpture, on very well pre- 

 served specimens, of microscopic striae which are exceedingly fine all over the 

 shell, and of about ten strong spiral lines at the base; longitudinal sculpture of 

 sharp-edged, close-set plications which are present on all the whorls (although 

 in some cases the whorls appear perfectly smooth, which is because the entire outer 

 surface has been removed by erosion) ; this handsome and even plication of the 

 whorls, extending over the last volution as well, immediately differentiates this 

 species from R. fowleriana; characters of base of shell and outer lip shown by 

 the second figure; the posterior canal in adult shells forms a sharply-ridged gutter 

 extending almost to the tip of the spire to which it is adherent. 



Height of shell 22, greatest width 8 mm. 



Remarks— This shell is one of the most abundant species in the Soldado 

 Lignitic fauna. 



The writer takes great pleasure in naming it in honor of Mr. I. N. Knapp, of 

 Morgan City, Louisiana, whose kind gift of deep well fossils has done so much to 

 further our knowledge of the depth and extent of the Quaternary strata of the 

 Gulf States. 



Locality.-- Bed No. 8, Soldado Rock, Gulf of Paria. 

 Geological horizon.— Lignitic Eocene. 



