PLATE XLYIII. 
Gyroceras spinosum. 
Page 382. 
See Plates 47, 49, 98, 99. 
Fig. 1. A chambered fragment, showing the inner volution of the shell and the bases of one of the lateral 
rows of spines. The air-chambers near the apex are numerous, becoming gradually deeper 
toward the aperture. Schoharie grit. Schoharie, N. Y. 
Fig. 2. A small, compressed fragment, showing somewhat deeper air-chambers than in the preceding 
specimen. Schoharie, N. Y. 
Fig. 3. Lateral view of a fragment, preserving its natural, uncompressed form, showing portions of the 
test and the bases of several of the lateral and ventral spines. Schoharie, N. Y. 
Fig. 4. Lateral view of a portion of the outer volution, preserving the chamber of habitation, with about 
twenty air-chambers. The bases of two lateral rows of spines are obscurely shown in the 
specimen, as represented in the figure. Schoharie, IV. Y. 
Fig. 5. Ventral view of a small, well-preserved individual, showing the enlargement of the tube, the sinus 
in the striae, and the two rows of spines, with the revolving ridges ornamenting the ventral side 
of the tube. A lateral view of this specimen is given on plate 98. Schoharie, N. Y. 
