ADDEXDA. 357 



It was thought they miglit possibly be steam-hoat ashes, as the 

 steamers that ply between this country and Europe pass that way. 

 Specimens of these were obtained from the ash-pit of the Baltic and 

 other sea steamers, and examined through the microscope. The 

 examination only satisfied the professor still more completely as 

 to the volcanic origin of the others. 



Thus the question is fairly presented, Where did these " Plu- 

 tonic tallies" upon the currents of the ocean come from ? Did 

 they come from the volcanoes of Mexico and Central America, 

 which have been known to cast their ashes into the Gulf of Mex- 

 ico, and even as far as the island of Cuba ? If so, the Gulf Stream 

 would have strewed them along the coast of the United States. 

 But specimens from the bed of the Gulf Stream off our coast have 

 been obtained by the Coast Survey, and subjected to the micro- 

 scope, and no volcanic cinders have been found in them. This 

 negative fact, together with the positive one that they are heavier 

 than the organic tallies which mark the footprints of the Gulf 

 Stream as it travels across the ocean, seemed to place those vol- 

 canoes as the source of these cinders out of the question. 



Nor do I perceive by what channel they could have been con- 

 veyed to the place where the deep-sea apparatus fished them up 

 from any of the volcanoes that are now in activity. They were 

 out of beat of the East Greenland current, and seemed to be too 

 heavy to carry far. I therefore turned to the region of extinct 

 volcanoes, and was immediately led to suspect the Western Isl- 

 ands as the probable source. The fact that the cinders were 

 coarse and heavy in comparison with the shells among which they 

 were found is very suggestive, for it tends to confirm this conjec- 

 ture. That no traces of volcanic action are found except in the 

 deep trough of the Atlantic, would seem to indicate that in this 

 part of the Gulf Stream they had, on their way to the north, sunk 

 below the submarine step which leads up from the depth of the 

 ocean to soundings off the Irish coast.* 



These specimens — ^bits of down from the bed of the ocean — ap- 



* Captain Stellwagen, U. S. Navy, has just informed me that the New England 

 fishermen often bring up with their hooks specimens of volcanic scoria from the 

 south shoals of Nantucket. 



