Hayden.] "^^^ [May 6, 



the lateral extremities; beak not incurved. Surface of both valves orna- 

 mented -with sharply defined, slightly curved, unequal radiating plica- 

 tions, and finer unequal striae, which, on the central regions of the valves, 

 are more or less gathered into five or six fascicles, the middle one of which 

 corresponds to the sinus in the other valve. 



In its surface markings and sinuous dorsal valve, this species is much 

 like a form from the upper Lingula-flags of Wales, referred by Mr. David- 

 son, doubtfully, to 0. lenticularis, Wahlenberg. It is much more ex- 

 tended on the hinge line, however, and has the radiating costae and strise 

 more strongly defined on the central region, and more nearly obsolete on 

 each side. From its affinities, it seems to be a Lower Silurian species, but 

 as no other fossils were found with it, its exact age may be somewhat 

 doubtful. It is unlike any Devonian or Carboniferous form known to me. 



Grater's Falls. 



2. Merista? (undetermined). 



3. Opliileta complanata, Vanuxem, or a very closely allied species. 



4. Bucanella nana, Meek. 



Very small, and much like Bucania trilohatus, Hall, but much smaller, 

 with proportionally larger umbilicus, and its three or four volutions increas- 

 ing less rapidly in breadth, both transversely and in the direction of the 

 plane of the shell; while its middle lobe is proportionally narrower, and 

 embraced by each succeeding turn. 



As these little shells want the remarkable expansion of the aperture 

 characterising Biccania, and show no traces of the mesial dorsal band, cor- 

 responding to a dorsal sinus in the lip ; as in Belleroplion, they seem tome 

 to belong to an undescribed genus, for which I would propose the name 

 Bucanella. 



5. Pleurotomaria f or BapJiistoma. Merely indeterminable lenticular 



casts. 



6. Endoceras. Small undt. sp. 



CAKBONIPEROUS SPECIES. 



Moleen Station. 



1. FitsuUna cylindriea, Fischer? 



2. Syringopora (undetermined). 



3. CampopTiyllum, like C. torquium, Owen, sp. From the Upper Coal 



Measure, along the Missouri, at Rock Bluff, and near there in Ne- 

 braska and Iowa. 



4. CJiaetetes (undt. massive sp). 



5. ProducUis Nehrascensis, Owen. 



6. Spirifer (Martinia) like 8. planoconvexus, Shumard. 



7. Bellerophon ?\ a rude cast ; may be a Nautilus or Goniaiiie, as it is not 



in a condition to show septa, if any exist. 



Sangre de -(Jliristo Pass, South Colorado. 



8. Productus semireticulaius, Mart, (sp.) 



9. Productus punctaiiis, Martin, sp. 

 10. AtJiyt'is subiilita, Hall (sp). 



