flfhfocene f*hanf/e.<i of Lt>vel. — TfeGt'f^r. 29 
After that, the ymrtions mentifmod bcgjin again If) paiticipato in 
the great contin«Mital upheaval, which seems to be still going on, 
though probably at a muoh rediiceil rate. 
I NVKS'l'Ki.VI'IONS IN XoKTII A.MKHK'A. 
(flint rratioiis. 
The very interesting and valna])le investigations of (jilbert, 
Upham and S[)encer, have shown that the shore-lines along the 
great lakes in the interior of eastern North America have been 
unequally uplifted more toward the north than toward the south, 
and this seems to be (piite in accordance with the generally 
adopted opinion in regard to the marine deposits along the Atlan- 
tic coast. This opinion seems to have l»een founded principally 
upon the ditf'erent hights to which marine shells could be traced 
in different tracts, this kind of evidence being the most indis- 
putable, though on the other hand atl'ording onl^- minimum 
figures. Concerning other proofs, as shore-lines, terraces, deltas 
and sediments of supposed late glacial age and marine origin, the 
opinions of different authors have been much more divergent. 
As examples of this diversity of opinictn the following figures 
may be (pioted: a few only ref(>r to shell localities. 
In his Manual of (ieology (IS);:')), .1, I). Dana mentions for 
the highest marine deposits: 
South of Nf^w York, seldom over 10-15 feet. 
At Brooklyn, bonji Islatui HK) "' 
In Soutliern New EnKhmd 3(»-85 "' 
In Maine, not more than 200 
At l>ak(' Champiain 468 " 
At Montreal, above Lake St. I'l'ter 470 "' 
In Harrow's Straits l,(l(l(» " 
In N. S. Shaler's paper on llecent changes of level in Maine 
(1874), we find for 
New York City a few feet. 
Deer Islt', in .Maine, al least L'do 
Belfast, '■ a 1 tout L'r)(i 
Between .Milln-id^c and Maeliiasport, at least loo 
At Labrador. '' l.ooo 
On the ( Jrecnland ( 'oast '• 2,000 
The same author in latei- papers assumes foi' 
Nantucket Island (ISS!»). at least :iOO feet. 
(;aj)e Ann (IS!)0) ].'«)- 100 "• 
Mount Desert MSHi)) ] .;«M)- ! .OOt I •' 
