NOTES. 445 
mikie and Keweenawan rocks, which are often full as favorable in nature to the oceur- 
rence of such remains as their supposed equivalents in the east. (2) It disregards the 
unconformity between the Animikie (and Huronian generally) and the Keweenaw 
Series, which unconformity finds no parallel in the eastern series, as given by Win- 
chell. (3) It disregards the immense and tar more striking and pronounced uncon- 
formity met with in the western succession between the Keweenaw Series and the 
overlying sandstones, which break not only finds no parallel in the east, but is to be 
contrasted with the gradation of the New York Potsdam into the overlying Calciferous 
Sandrock. (4) It parallelizes the Keweenaw Series, which approaches a thickness of 
50,000 feet, of which fully 15,000 are of purely detrital matter, with a sandstone only a 
few hundred feet thick. 
The lithological evidence advanced is hardly worth discussion, because of the well- 
recognized untrustworthiness of such evidence when applied to the comparison of rock 
formations at long distances apart. Winchell’s assertions, however, of a lithological 
correspondence between the New York Potsdam and the Keweenaw Series will not 
bear examination. In his own words, the New York formation “is a red or gray loose 
sandstone, often tilted or faulted, also metamorphosed, and then having the name of 
quartzite.” We look in vain in it for the great beds of porphyry-conglomerate, the 
immense thicknesses of basic and acid eruptive rocks, and the black shales of the Ke- 
weenaw Series. Even the sandstones of the two formations do not approach each 
other in character, those of the typical Potsdam being described as distinetly quartzose, 
whereas those of the Keweenaw Series are only very subordisately so, being composed 
almost wholly of fragments of the feldspars or felsitic matrix of the acid eruptives of 
the same series. The occurrence in the Keweenaw Series of beds of metamorphic 
origin, including ‘ gneiss, syenite, and hard, red quartzites,” as stated by Winchell, I do 
not admit. Gneiss is never met with. Peculiar red rocks, to which the name of sye- 
nite may be applied, are met with in the series, but are plainly of an intrusive nature. 
Rocks to which the name quartzite could be applied I have never seen; certainly they 
must be very rare, if they occur at aH. Portions of sandstone beds locally indurated 
by a quartz infiltration I have occasionally seen, but such rare and unimportant oceur- 
rences would hardly warrant the mention of quartzite as a characteristic of the forma- 
tion. On the other hand, there is a distinct similarity between the typical Potsdam as 
described and the so-called Potsdam of Central Wisconsin, where a quartzose compo- 
sition, with local indurations due to quartz infiltration, and local developments of red 
sandstone, often of considerable thickness, are prominent features. 
The paleontological evidence advanced by Winchell consists in the occurrence, in 
the Calciferous Sandrock of New York, and in its extension into Canada, of a fauna 
nearly allied to that of the lowest fossiliferous sandstone of the Mississippi Valley. 
Accepting the statement as to this similarity so far as it goes, I have to say, (1) that the 
evidence is too meager to establish a complete equivalency between the Calciferous 
Sandrock and the Mississippi Potsdam; (2) that even if it were not so, it would remain 
to show that the Potsdam itself is not merely a downward continuation of the Calcifer- 
ous, the few fossils that occur in it being insufficient to disprove this relation, while the 
grada ‘ion of the Potsdam into the overlying Calciferous is a distinct indication of such 
a relation. 
In conclusion, then, I have to say that it seems to me quite plain that the horizon 
