286 The American Geologist. November, i90i. 
ural features, those observed being wholly disproportionate 
to the magnitude of the result. 
The appearance of barren shale partings, going east from 
Niagara county, is evidence that the limestone making phase,, 
dominant during the formation of these lenses, was interrupted 
by the incursion, froni time to time, of mud-bearing currents 
from the shores of the eastern interior sea which lay to the 
north and east. Disarticulated brachiopods and dismembered, 
partially triturated, crinoidal remains, of which the including 
layers are composed, and occasional overturned Favosites 
found upon some of the surrounding limestone surfaces are 
regarded as other indications of currents. But the uniform 
thickness throughout different parts of the layers and their per- 
sistency, indicate that these currents were weak. Further, the 
remains of Bryozoa and other organic matter comprising these 
masses, often bulky of form, if enmassed by the impelling force 
of moving water would require strong currents or even wave 
action. But the absence of water-worn and broken shells with- 
in these masses, and of cross bedding and current channelings 
in the surrounding limestone is significant. This is strikingly 
illustrated by the beehive-shaped mass at Niagara gorge above 
the whirlpool. [PI. xxvii, Figs. 5 and 6.] This heap of 
organic remains rises steep-sided eight or nine feet above the 
surrounding limestone surface, and nowhere either in or about 
the mass are the above conditions indicated. 
The fine preservation of much of the organic material 
seems to point to its comparatively undisturbed condition 
after death ; and the great number of rare forms, some 
not found outside of these masses, can hardly be credited 
CO the sorting or selective power of currents or eddies. 
There appears no reason to doubt that these masses were to- 
some extent influenced by currents, but that any of them owe 
their origin wholly to this agent is improbable. The gentle 
movements of the water are regarded as only a modifying in- 
fluence to some more important agent. 
By Organic Grozvth : The explanation of origin is found in 
the bryozoan matter. The axes in all cases are large masses of 
fistuliporids. These organisms are always in plosition of 
growth, and practically do not occur outside of the lenses. 
That their position is normal is determined by examining their 
