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102 CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 



microscopic lines of growth; number of known whorls three, evenly rounded, full, 

 slightly shouldered at the upper portion; suture impressed, marked by a narrow 

 channel; aperture and characters of the columella concealed by the silicious 

 matrix. 



Height of shell approximately 30, greatest width 21 mm. 



Remarks. — The only other Amauropsis described from the Midway Eocene is 

 A. tombigbeensis Harris from Alabama, which is wholly unlike the Soldado shell. 

 There is also in the Paleontological Museum of Cornell University an undescribed 

 Midway species somewhat like the latter but smaller. The nearest ally of the 

 Soldado shell is A. perovata Conrad from the Claibornian Eocene. 84 



It is a curious fact that all the living species of Amauropsis are in Arctic and 

 Antarctic seas, yet a number of Tertiary species lived like the Soldado shell in 

 tropical and subtropical waters. Has the genus fled to the less crowded frigid 

 oceans to escape the pressure of competition in the tropics? 



Locality. — Bed No. 2, Soldado Rock, Gulf of Paria. 



Geological horizon. — Midway Eocene. 



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Amauropsis ? guariqueenensis new species. Plate XIII, Figure 10. 



Remarks. — In a limestone ravine near Guariqueen, Venezuela, there are traces 

 of quantities of the remains of large gastropod shells. 



Several species are represented; but it is impossible to separate the fossils 

 from the rock. Hundreds of sections cutting through the shells at various planes 

 were observed on slabs of the limestone, but not a single complete specimen was 

 to be had. 



A drawing is given of the best specimen obtained after treating with various 

 acids in the unsuccessful attempt to disclose the whorls. The shells are all 

 turned to a blackish crystalline spar, and form an integral part of the excessively 

 indurated limestone. 



The general form of the shell indicates a large species of Amauropsis. Others, 

 with very oblique outlines, suggest such forms as Neritidomus from the Brazilian 

 Cretaceous figured in White's monograph. 



Locality. — Along the trail from Pitch Lake to Guariqueen, Venezuela, in a 

 limestone gorge. 



Geological horizon. — Probably Cretaceous. 



Amauropsis smithiana new species. Plate XIII, Figures 11, 12, 13. 



Description. — Shell of moderate size, varying considerably in that respect; 

 substance thin and fragile; number of whorls known, five, very convex, gently 

 rounded, slightly shouldered beneath the suture; shell entirely without sculpture, 

 perfectly smooth, suture impressed; aperture nearly semi-lunar; callus very thin. 



Approximate height of largest specimen 18, greatest breadth 17 mm. 



Remarks. — This is the commonest species in the Lignitic fauna of Soldado. 



84 Bull. Am. Pal., vol. I, p. 49, pi. 1, fig. 1. 



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