Miscellanies. 375 



weathered shells of kindred species. The figure of the L. acuta rep- 

 resents the columella as intruding upon the aperture, which is not the 

 case with this shell. 



6. Cyclas elegans. C. testa bizonata, subglobosa, rhombico or- 

 biculari, equilaterali, eleganter et tenuissime striata, natibus haud pro- 

 minentibus; umbonibus tenuibus ; infra albo-coerulescente. 



Rem.arks. — This shell is remarkable for its inflation, which contin- 

 ues far over the disk of the shell, and terminates quite abruptly near 

 the margin. The circumference very nearly resembles that of the 

 C. calyculata, except that it is less curved below; that shell however 

 is flatlish and has prominent beaks. C. rhomboidea, Say, approaches 

 this in form, but is much less inflated between the umbo and margin, 

 has very coarse striae and is destitute of the paler zones, which' in 

 this shell appear to be a constant character. 



March 11, 1840. — George B. Emerson, Esq., President, in the chair. 



Dr. Storer stated that he had received information from Dr. Kirt- 

 land, of Ohio, that the descriptions and figui*es of the following fishes 

 of the western waters, by the latter gentleman, had been completed ; 

 viz. Centrarchus hexacanthus ; Polyodon folium ; Catostomus Du- 

 quesnii ; C melanops ; C. gracilis ; C. anisurus ; C. elongatus ; Hy- 

 odon turgissus ; Pimelodus cupressus ; P. limosus ; P. cceruleus ; Ca- 

 tostomus bubalus ; C nigrans ; Chatoessus ellipticus ; Lepisosteus 

 oxyurus ; L. platostomus; L. ferox ; Leucioperca Americana; Aci- 

 penser nudus ; A. macrostomus ; Anguilla lutea ; Ammocoetes con- 

 color; Labrax chrysops ; Icthelis macrochira. 



A specimen of shell limestone from Machias, Me. presented for the 

 cabinet by Lynde M. Walter, Esq., was laid on the table. Dr C. T. 

 Jackson stated that this was from the sandstone formation in Machi- 

 as, Me., and was composed principally of univalve shells. It had 

 been consolidated by the heat of the trap which had forced its way 

 through it, so that in some instances it had been converted into com- 

 pact and even into crystalline limestone ; occasionally the limestone 

 has been broken, by the intermixture of the trap, so as to form lime- 

 stone breccia. ,^ 



March 18, 1840. — Thomas A. Greene, Esq. in the chair. 



Dr. M. Gay read the following communication from A. A. Hayes, 

 Esq., of Roxbury, on the Native Nitrate of Soda, found in South Peru. 



The existence of beds of Nitrate of Soda in Peru has been long 

 known, and tlie inhabitants of a most arid and desolate region, have 

 made it by simple operations an important article of commerce and 

 manufacture. 



