214 ANNUAL OF SCIENTIFIC DISCOVERY. 



the valley of the River Platte, not far from Omaha, and am now 

 satisfied that the whole extent of the country between the Alle- 

 ghanies was one unbroken glacier bottom. The scratched pebbles 

 found among the loose materials of the great prairies confirm this 

 view. For similar reasons, I am satisfied that the valley of the 

 Amazons has not been under the level of the ocean since the 

 tertiary period." Report upon Deep-Sea Drcdgings in the Gulf 

 Stream during the Third Cruise of the U. S. Steamer Bibb, 

 addressed to Prof. Benjamin Pierce, Superintendent U. S. Coast 

 Survey ; in Bulletin of the Museum of Comparative Zoology, 1869, 

 No. 13, p. 363. 



In the last deep-sea exploring expedition of H.M.S. Por- 

 cupine, in the Bay of Biscay and along the Atlantic coasts of 

 Spain and Portugal, Mr. Gwyn Jeffreys procured, from a very 

 considerable depth (in the neighborhood of 1,000 fathoms), many 

 species of mollusca, some of which had hitherto been supposed to 

 exist in the fossil state only, having been found in the latter 

 tertiary formations of Sicily and Calabria. A number of the 

 species are those which inhabit Arctic seas, and Mr. Jeffreys 

 submits for consideration the following questions: 1. " Have not 

 all the deep-sea species of European mollusca originated in the 

 north, and spread southwards in consequence of the great Arctic 

 current? " 2. " Inasmuch as the Pliocene division of the tertiary 

 formation is now ascertained to contain scarcely any extinct 

 species, and as future explorations may reduce the percentage of 

 such species to nil, may not that artificial division hereafter merge 

 in the quaternary formation, and the tertiaries be restricted to 

 eocene, miocene, and pliocene? " 



Chemical Examination of Mud from the Bed of the Atlantic. 

 James Mahoney. The author had examined chemically a speci- 

 men of mud from the deepest dredging made by the Porcupine, 

 2,435 fathoms. The composition was found to be as follows : 



Silica, 26.60 



Peroxide of iron and phosphates, 3.80 



Protoxide of iron, 0.08 



Carbonate of calcium, 58.80 



Carbonate of magnesium, 1.76 



Sulphate of calcium, trace. 



Soluble salts, 4.20 



Organic matter, 2.30 



Water, 2.50 



100.04 



The silica was found, under the microscope, to consist chiefly of 

 minute structureless fragments, some of them being crystalline. 

 A small number of diatoms were also found. The carbonate of 

 calcium consisted of larger organisms (class Foraminifera) , some 

 still containing the small particle of jelly-like matter constituting 

 the animal substance of these organisms, and called sarcode by 

 Dujardin. These doubtless yielded the organic matter noted in 

 the analysis. The soluble salts were accounted for by the evapo- 

 ration of the sea-water with which the mud was charged when 



