451 Dominican Sections — Maury 35 



only. At 870 feet an unfossiliferous limestone bed was exposed, 

 at 660 feet a bed of sandstone, at 600 feet a second sandstone 

 bed outcropped, at 540 grayish and yellowish fossilferous clays 

 were found. The general surface of the Las Caobas plain is 480 

 feet. In the fossiliferous yellow clays in an arroyo were the fol- 

 lowing molluscs : — 



List of Species 



Calliostoma Grabaui, n. sp. Pecten eugrammatus Dall. 



Area lomasdesamba, n. sp. Pecten Thetidis Sby. 



Barbatia cf. Bonaczyi Gabb. Pecten vaginulus Dall. 



Scapharca Henekeni, n. sp. Amusium papyraceum Gabb. 



Glycimeris acuticostata Sby. Myrtsea lomasdesamba, n. sp. 



Ostrea virginica Gm. Cardium sambaicum, n. sp. 

 Cardium serratum Linne. 



Rio Amina. — Several bluffs composed of hard, light blue 

 clays were examined on the Rio Amina between Hato Viejo and 

 Potrero. See Sketch Map of Route (14) and (15). The bluffs 

 at Hato Viejo being farther down the river and hence higher in 

 the section, were found to be nearly barren, containing only a 

 few fossils too poorly preserved to collect. Further up the river 

 the bluffs become more fossiliferous but the fauna was still rela- 

 tively scanty. 



The dip along this portion of the river is very variable, 

 changing from northerly to horizontal and southerly, thus prov- 

 ing the presence of an anticlinal fold. In the distance traversed 

 the lower beds were not encountered. 



Miss Rathbun kindly has identified the chelae which we col- 

 lected on the trail to Potrero as those of Petrochirus, a genus with 

 two living species, one West Indian, one on the west coast of 

 America. Toula says he found Petrochirus in the Gatun beds. 



List of Species 



Acteocina ovum-lacerti Gpy. Phos Gabbii Dall. 



Terebra Gabbi Dall. Phos elegans Gpy. 



Terebra amitra Dall. Phos fasciolatus Dall. 



Terebra haitensis Dall. Strombinella acuformis Dall. 



Terebra cirrus Dall. Bursa Amphitrites, n. sp. 



