356 Methods of Stratigraphy. — Winchell. 
Some of the results of the new method of work may be here 
re-capitulated somewhat more systematically, viz. : 
1. The Huronian, as defined by Logan and Murray has been 
re-examined, and the essential correctness of their stratigraphy 
and of their geological map has been affirmed. 
2. Below the strata enumerated by them is a great series of 
strata divisible into at least two parts, placed unconformably 
below the Huronian. These have been examined and named 
Keewatin and Vermilion groups, but by the Canadian survey 
they are claimed still as belonging in the Huronian. 
3. The strata of the Huronian proper are non-crystalline and 
plainly fragmental, while those underlying strata are distinct- 
ly different, the Keewatin consisting very largely of volcanic 
ejecta, simply arranged and consolidated by the agency of 
oceanic water and later metam Orphic forces, and the Vermil- 
ion of the same re-crystallized by hydrothermal fusion. 
4. That the distinctness of the true Huronian is every- 
where observable both on account of its different lithology and 
its basal fragmental conglomerates that lie unconformably on 
the Keewatin, on the Vermilion, and even on the Laurentian. 
5. I would add a further general truth, to which the work 
of the Minnesota survey has arrived, viz : the true Huronian is 
divisible into two non-conformable parts, the lower being the 
slate and slate conglomerates and the upper the quartzyte and 
quartzyte conglomerates. 
6. And still another, the upper part of the true Huronian 
was characterized by frequent and enormous outflows of basic 
eruptive rock, and by some of acid rock, the equivalent, as 
at first supposed by Logan and Hunt, of the recently named 
Keweenawan. 
The re-construction of the Huronian and the treatment of 
the correlated terranes. The results above enumerated are suf- 
ficiently important to call for a sweeping reconstruction of the 
prevalent idea of the Huronian system. That it is a system is 
shown by its wide range of strata (at least 18,000 feet), its un- 
conformable relations to the underlying and overlying series, 
and its relations of apparent identity to other terranes (Ta- 
conic, Lower Cambrian) which are recognized as systems by 
the common consent of geologists. That the Huronian has 
been made to include much more than it did originally is not 
the fault of the authors of the name. It is but justice to tbem 
