rLATE J III. 



Fig. 1. Oethodesma cuneiforme, n. sp.— View of the right side of a cast, . 314 



la. View of the anterior end. 

 Fig. 2. Cleidophorus CHICAGOENSIS, n. sp.— View of the right side of a east, 

 though too much flattened, in appearance, to show the true gibbous 



form of the fossil, 314 



2a. Dorsal view. 

 Fig. 3. Ambonychia robusta, n. sp. — View of the right side of a cast preserving 

 part of the markings of the shell, though the illustration does not show 

 the abrupt bending over of the fossil on the anterior side, nor the ven. 



tricose form of the shell, 315 



3a. Anterior view of the shell of a very finely preserved specimen. 

 Fig. 4. View of two joints of an undetermined fossil. 

 4a. Sectional view, showing its fibrous character. 

 Fig. 6. CUNEAMYA PARVA, n. sp. — View of the right valve, though the anterior end 

 is a little defective, in showing a subaugular form, where the fossil is 



beautifully rounded, . 316 



oa. Dorsal view of the same specimen. 

 Fig. 6. Orthodesma occidentale, n. sp.— View of the right valve of the shell, 316 

 6a. Dorsal view of a cast, though showing too many concentric lines near the 

 beak. 



