Report of U. S. National Museum, 1897.— Flint. 



Plate 51. 



Fig. 1. ORBITOLITES MARGINALIS Lamarck, < by transmitted light.) See page 304. 



a. Section. 



Fig. 2. ORBITOLITES DUPLEX Carpenter. See page 305. 



a, t. Sections. 



Fig. 3. ORBITOLITES DUPLEX Carpenter, (by transmitted light. i 



