Editor inl Comment. 47 
more in length, largely changed to mica, also to pure quartz. 
These were from Villeneuve, Quebec. 
In the Canadian Survey exhibit was an instructive map, 
which under the animated explanation of Dr. Selwyn was 
made to point an interesting geologic fact. This map was 
made by Mr. H. Fletcher, and covered an Arehean area in 
Nova Scotia and Cape Breton, an area which is most thor- 
oughly worked in respect to the relations of the parts of the 
Arehean. Dr. Selwyn is thoroughly convinced of the cor- 
rectness of Mr. Fletcher's view, that there is no possibility of 
separating the Canadian Huronian from the Laurentian by any 
stratigraphic distinction, such as a non-conformity. Mr. 
Fletcher has despaired of making an}- fixed stratigraphic 
separation. His map shows one color for both, but they are 
marked by the letters A and B, meaning upper and lower Ar- 
ehean. The passage from one to the other is gradual when- 
ever the stratigraphic succession is examined, but local irreg- 
ularities occur. 
Under "Laurentian," H. A. Ward had a show of Eozoijn 
and, strange to say, Cryptozoon proliferum, from Saratoga, N. 
Y., labelled from the "Potsdam/' That is a well-known ( !al- 
ciferous fossil. The tendency to crowd the term Potsdam 
upward, apparently to make it cover the western so-called 
Potsdam, which is near the Calciferous, is absurdly exempli- 
fied in this fossil, since its western analogue, Cryptozoon min- 
nesotense, is found only in strata far above even those western 
strata to which the term Potsdam has been applied. At that 
rate, the whole of the northwestern Upper Cambrian must be 
included under the term "Potsdam ;" and the Lower Magne- 
sian, with its subdivisions, and the intervening sandstones. 
will lose their significance as coordinate members of the 
Cambrian. It would be difficult to extend the effects of a 
stratigraphic misnomer to a greater extreme. The Cryptozoon 
in Ward's collection was very fine, some large lenticular 
pieces being sliced and polished. These were put in juxta- 
position with Eozoijn because of their apparent structural 
organic resemblance, and it was indeed quite obvious. It may 
be said that the discovery of Cryptozoon furnishes a strong 
argument for the original claim of Eozoo'n. n. u. w. 
