SOLARIUM. 321 
Straparollus exsertus is a fossil of the Murchisone-zone of Bradford Abbas and 
Coker, where it is extremely rare. Fig. 4 represents a more depressed variety 
from North Dorset, but the precise horizon and locality are unknown, 
254. STRAPAROLLUS, cf. aLTUS, d’Orbigny, 1853. Plate XXVI, fig. 5. 
1852-3. SrRaparottus attus, d’Orb. Terr. Jur., vol. ii, p. 814, pl. ccexxxii, 
figs. 5—8. 
Description : 
Diameter ; . : : Sele Srnnrie 
Height ‘ ; : . 10 mm. 
In the specimen under notice the width and height are nearly equal; spire 
about one-fifth the total height. The whorls externally (six) are subquadrangular 
to trigonal, flat atop, and occur in steps. The marginal tuberculations are well 
developed and rather close. The upper angle of the body-whorl is a right angle, 
but the flank rapidly contracts towards the umbilicus, which is of moderate 
dimensions and surrounded by a few large and pointed tubercles. Aperture 
trapezoidal and produced in front. 
Relations and Distribution.—This form seems to be a further step in the direction 
of Solariwm; though about three times the size of d’Orbigny’s type from the 
Bathonian of Langrune, the resemblance is strong. A single specimen from the 
Inferior Oolite near Beaminster. 
Note.—Besides the species of Discohelix and Straparollus enumerated above, 
we find here and there throughout the Inferior Oolite specimens which from 
imperfect preservation it is impossible to diagnose, e. gy. below the Opalinus-bed 
at Burton Chiff. Again, there is a very thin form in the Opalinus-bed of the 
same locality: a similar form occurs in the blue stone at Duston. 
Genus—Sorarium, Lamarck, 1799. 
Shell orbicular, conical-depressed, largely wmbilicated ; whorls subtrigonal and 
sloping ; spire regular, nucleus oblique ; umbilicus deep, the outer margin crenulated ; 
aperture trapezoidal. 
D’Orbigny seemed to entertain no doubt as to Solariwm having been a Jurassic 
41 
