Wright.] 
156 
[Dec. 19, 
Bloomsburg in the Catawissa Hills, Luzerne county, which he at- 
tributes to the Columbia floods, as reaching to the height of five 
hundred feet above the Susquehanna. It will be observed, how- 
ever, that this is very near the margin of the terminal moraine as 
laid down by Professor Lewis and myself across the Susquehanna 
valley. But both of us became convinced that we did not, when 
examining that region, give sufficient attention to what we after- 
wards denominated the “ fringe, ” — that is, to the scattered indi- 
cations of direct glacial action found over a belt more or less 
wide in advance of the heavier deposits, which could more properly 
be called “ terminal moraine .” 1 In our report on this locality we 
refer to occasional transported boulders found upon hilltops in front 
of the moraine in the vicinity of the Susquehanna and Delaware 
rivers, and which, Professor Lewis remarks, it is difficult to explain, 
upon any theory of a flood, and that they may be of like origin with 
the fringe farther west. In view of these facts, therefore, I suspect 
at present that the highest boulders, to which Mr. McGee refers on 
the Catawissa hills in the vicinity of the Susquehanna, are the di- 
rect results of glacial action ; the ice itself having extended that far 
below the terminal moraine. I am confirmed in this belief from the 
fact, that below this point on the way to Harrisburg, Mr. McGee 
does not find the deposits much above the two hundred foot line at 
which Professor Lewis had limited it. Until further examination 
of the district with these suggestions in view, or until a more spe- 
cific statement of facts than we find in Mr. McGee’s papers, it 
would therefore seem unnecessary to postulate a distinct glacial 
period to account for the Columbia formation. 
Time would fail us, however, to enter into the whole discussion 
relating to the various stages of glaciation brought to light by re- 
cent investigations in North America. But no matter which view 
prevails, whether that of two distinct glacial epochs or of one pro- 
longed epoch with a mild period intervening, the Columbia deposits 
at Claymont, in which these discoveries of Mr. Cresson have been 
made, are older (perhaps by many thousand years) than the deposits 
at Trenton, N. J., at Loveland and Madison ville, Ohio, at Little 
Falls, Minn. (of which more particular account was given this society 
a year ago), and at Medora, Ind., of which Mr. Cresson has given 
us an account to-night. Those all belong to the later portion of the 
glacial period, while these at Claymont belong to the earlier portion 
J See “Pennsylvania Report, ” Z, p. 201. 
