394 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
beyond Fishing Lake, the overlying whin, stratigraphically the 
highest area in the region, stands up as a hill sloping west, and 
presents an abrupt fault-scarp to the east. The surface of the 
higher hills may be taken as approximately the level of the pene- 
plain. The etching has been due to the uplifting of blocks into 
heights of more rapid denudation, in consequence of which the 
durable whin overlying the auriferous slates has been removed and 
the softer rock below eroded to a lower level than the whin of the 
unfaulted areas'to the east and west. Both fault-blocks in which 
the beds plunge westward have their steepness of surface in 
accordance with the dip of the beds, although not so high. At 
East Waverly the whin cap is eroded over the axis of the fold 
to within a few feet of the slate, and a view from the west shows 
a depression of the crest-line at that point, indicating a near 
approach to the unroofing of the anticline. 
The distribution of mining regions and the shapes of the outcrop¬ 
ping areas are due to the intersection of domes of various shapes by 
the peneplain surface. 
History of tiie Series. 
The question of the age of the series is as yet a matter of doubt, 
and it is probable that this uncertainty will continue until fossil 
evidence has been found. I can add nothing to what is already 
known, for all the “fossils” I have found turn out to be concretions 
which so far have not shown even an oroymic nucleus. The most 
rational view appears to me to be that of Becker (’95), who, after 
summing up the evidence given by various writers, concludes that 
the sediments are more probably Algonkian than Cambrian. 
The following is an attempt to reconstruct the apparent history 
of the series from the data which are available at the present time. 
Deposition, on a sea-floor somewhat irregularly rising and sinking. 
The lower division of the series is said to become coarser toward 
the top, indicating shoaling. Above this comes the finer grained 
upper member, which apparently shows a return to deeper water 
with more uniform conditions. 
Consolidation, gradually, by weight of added sediments. Despite 
this tendency the pressure from above was sufficient to keep that 
part now forming the series in a plastic state. The original thick¬ 
ness, even after consolidation, must have been several times that 
