PLATE XVII. 



Fig. 26 a. Section from CRIOCERAS PERCOSTATUS. 77 



Fig. 27. BACTJLITES CHICOENSIS. Natural size. 80 



a. Section. 



Fig. 28. BACULITES, Sp. indet. Natural size. 81 



I 



Fig. 31. ATURIA MATHEWSONII. Natural size. 69 



