40 THE NAUTILUS. 



of aperture 6 mm.; 5^ whorls. It will be figured in the present vol- 

 ume of the Manual of Conchology. 



Another species of unusual interest is a fossil Partulina which was 

 discovered by Dr. Cooke several years ago in a superficial road cut- 

 ting at the junction of Manoa road with the upper road, back of 

 Rocky Hill, which terminates the western ridge of Manoa valley. 



Only one Partulina has been known in Oahu hitherto, that being 

 P. dubia (Newc.). The present form, which I will call Partulina 

 montagui n. sp., is not related to dubia, but to such Molokaian spe- 

 cies as P. dwightii Newc. I regard these two Partulinas and the 

 few Oahuan species of Laminella as stragglers from the Molokai- 

 Lanai-Maui evolution-center, which reached Oahu before the sub- 

 sidence of a ridge which I believe formerly connected the islands. 



P. montagui cannot have been extinct for any great length of 

 time, as the specimens occur in the humus, only buried a few inches 

 below the turf. Probably the forest disappeared from where they 

 are found not more than seventy-five to a hundred years ago. It 

 must have been extinct in the early fifties, or it would surely have 

 been found by Newcomb, Gulick or Emerson. 



The shell is sinistral, perforate, ovate-conic, with acuminate spire, 

 thick and solid, sculptured with close, irregular wrinkles, the last 

 whorl malleated ; whorls 7, the upper ones nearly flat, the rest con- 

 vex ; suture superficial. Outer and basal margins of the peristome 

 expanded, thick, heavily thickened within; columellar margin thick; 

 columellar fold thick and moderately prominent. 



Length 25, diam. 14 mm. (108181 A. N. S. P.). 



Length 24.7, diam. 12.5 mm. (Ill colL Irwin Spalding). 



Length 26.9, diam. 13.1 mm. (33581 B. P. Bishop Mus.). 



THE UNIONE FAUNA OF THE OBEAT LAKES. 



BY BRYANT WALKER, SC. D. 



( Continued from page &$.) 



Now, according to the geologists, some time about the beginning 

 of the Cretaceous Period there was a great sinking of the land in the 

 Gulf region. It extended from central Texas east to the middle of 

 Alabama, and in a triangular shape north to southern Illinois. It 



