Review of Recent Geological Literature. 125 
pendent masses round which later traps and conglomerates adjusted 
themselves. These masses appear to have been lens-shaped. 
4. The Keweenawan beds were probably not laid down horizontal- 
ly and subsequently tilted, but accumulated on the sloping rim of a 
basin, which rim and slope they accentuated by their viscidity and rapid 
cooling. In this growth the acid rocks contributed more, pro rata, 
according to bulk than the basic. 
5. There is no evidence of special local subsidence due to the ac- 
cumulation of the Keweenawan rocks, but such subsidence must be 
considered, if it has occurred, as a differential change of level or pro- 
cess of mountain-building which began in pre-Keweenawan time. 
6. The Stannard rock, which is a reef off the extremity of Kewee- 
naw point, cannot be considered as necessarily a continuation of the 
felsyte rocks of the horizon of Mt. Houghton, but may be the focus 
of a separate eruption, or the remains of a mountain around and over 
which the 'Keweenawan lavas flowed. 
7. The rocks of Mt. Bohemia, a conspicuous part of the Bohemian 
range, are difTerent from all other rocks on Keweenaw point, embrac- 
ing augitic syenyte and orthoclase-gabbro, and those rocks form a 
mass probably intrusive in the melaphyrs. 
8. There is evidence that the upper portion of the Keweenawan 
series on Keweenaw point has suffered a slide-faulting, involving the 
strata above the Kearsarge conglomerate, by which they have been 
moved along an inclined plane a distance of nearly three miles, an 
important element in shaping the topography of the peninsula and in- 
timately connected with its copper deposits. 
9. This movement may have separated the Greenstone and its over- 
lying beds from the summ.it of the Bohemian range. Originally the 
southeastern face of the Greenstone escarpment may have coincided 
with the southeast face of the Bohemian range. 
10. On Keweenaw point there are at least five more or less marked 
horizons of medium acid to very acid rocks. 
11. The "eastern sandstone", although apparently running below 
the traps of the Keweenawan at some places, really belongs above 
them, and all appearances of subter-position must be interpreted in 
some way consistent with the later date, and normal superposition 
of that sandstone. 
12. The south side of Keweenaw point was an old sea cliff and not 
?. fault scarp. Against and on it the eastern sandstone was deposited. 
Any faulting that may be observed between the eastward or southward 
sloping traps and the overlying sandstone is simply a contact phenom- 
enon. 
13. The valley in which Portage lake lies is not due to a fault 
across Keweenaw peninsula. 
The volume is terminated by an appendix on "the crystallization 
of calcite from the copper mines of lake Superior," by Mr. Charles 
Palache, who definer. 87 different forms, 32 of them being new to 
calcite. 
