14 
ORIGIN OF LIFE IN AMERICA 
Professor E. Morse first discovered the shell of this snail 
among the contents of ancient “ kitchen-middens,” those 
peculiar refuse heaps of primitive man, on some of the. islands 
off the east coast of Maine. He pondered over this singular 
mystery and finally came to the conclusion that the snail must 
have slowly wandered, during a long series of centuries, from 
the Old World to the New, by means of an ancient North 
Atlantic land bridge. Mr. Johnson,* * * § to whose instructive 
paper I am indebted for this information, states that Dr. 
Binney and Professor Cockerell concurred in Professor 
Morse’s opinion. He also informs us that the Rev. Winkley 
and he were of opinion that the arrival of the snail Helix 
hortensis in America must have taken place before the advent 
of the Glacial Epoch. 
This theory, as can be imagined, was by no means gene¬ 
rally accepted in America. All doubts, however, as to 
the claim of Helix hortensis being an indigenous American 
species are now set at rest, through the discovery by 
Dr. Dallf of the shell of this snail in undoubtedly Pleisto¬ 
cene deposits in the State of Maine. Some naturalists might 
still be inclined to urge that greater facilities for occasional 
transport across the Atlantic may have existed in those remote 
times than at present, and that the argument in support of 
a land bridge is not convincing. No evidence, however, in 
favour of an ocean current from Europe to North America in 
Pleistocene times has as yet been brought forward, Avhile the 
conviction in the former presence of a land connection between 
north-eastern America and north-western Europe is based 
upon other biological observations. From a geological point 
of view we can scarcely hope to be able to determine the period 
or periods during which this land bridge existed. The bathy¬ 
metrical features of the north Atlantic, according to Pro¬ 
fessor Hull,:}: Dr. Spencer § and Dr. Nansen, || point to a pre- 
Glacial elevation of the land in northern latitudes. Dr. 
* Johnson, C. W., “ Distribution of Helix hortensis,” p. 73. 
t Dali, W. H., “ Land and Freshwater Mollusks of Alaska,” p. 20. 
\ Hull, E., ‘‘Submerged Terraces and Fiver Valleys.” 
§ Spencer, J. W., “ Submarine Valleys,” p. 224. 
|| Nansen, F., “ North Polar Expedition,” p. 192. 
