FOR THE ADVANCEMENT OF SCIENCE. 569 
lakes of Ontario and Erie to Minnesota. He argued that these plants 
were originally introduced by natural emigration along an ancient estuary, 
and that many of them remain to the present day in consequence of the 
M of conditions favorable to their preservation. He supposed 
at the plants about the salt springs in Northern New York were intro- 
— in the same way. The pre-glacial flora has been completely de- 
Stroyed by the'intense cold, and while a new creation might explain the 
existence of salt water plants about the springs, it would not show w 
these marine plants could exist in the far interior. There should be a 
questions, and therefore it was urged "o botanists should faithfully pre- 
serve the localities of all their specimen 
Professor T. SrERRY Hunt said the ecd of black iron sand upon 
many sea beaches has long been noticed both in Europe and America. 
Their origin is to be found in the crystalline rocks, from the disintegration 
of which these sands have been derived. The action of the waves, b 
virtue of the greater speci vity of these sands, effects a process of 
concentration, so that considerable layers of nearly puré black sand are 
ften found on shores expos nd & These black sands vary 
New England and the Gulf of St. Lawrence consist of magnetic oxyd of 
an 
garnet, the purest specimens holding from thirty to fifty per cent. of mag- 
netic grains. Such sands have long been es as sources of iron in 
India, where they are directly converted in mall furnaces into malleable 
rking it were, however, made in cont game onn., where the Rev. 
he London Society of Arts in 1761 awarded a medal to Mr. Elliot for his 
discovery. The working, however, was abandoned, and for a century no 
ttempts were made in America to use these sands. Some four years 
AMER. NATURALIST, VOL. IV. T2 * 
