Eruptive Debris at Taylor s Falls, Minn. — Winchell. 75 
surface exposure near the railroad at the level of the track. It 
here is coarse, composed mainly of trap masses, but has the 
same granular fragmental debris as a cementing material. 
The trap masses vary in color and texture. 
4. From these outcrops, and from the known dip and 
strike of the igneous beds within which this trap-conglomerate 
is embraced, it can be inferred that the strike of the lower 
conglomerate is from NW. to SE. about coincident with 
that of the trap. As to its thickness, while we can afBrm no 
more than was actually seen, we may infer from the topog- 
raphy throughout which the outcrops are distributed, that 
there is a greater thickness than 30 or 40 feet, and that 20a 
feet would be nearer the actual thickness. 
This conglomerate is not known on the east side of the 
river, and its dip and strike cause it to occupy only a narrow 
belt extending diagonally across the southern portion of Tav- 
lor's Falls. 
It is to be inferred, therefore, that at the date of the ac- 
cumulation of this rock the ocean occupied the place of Tay- 
lor's Falls. That in the near vicinity were active or extinct 
volcanoes, the ejections of which contributed to the sedimen- 
tary accumulations. These may not have been distinctly 
volcanic emissions, but may have been eruptions from fis- 
sures, and the cooling lava may have spread so widely as 
to form extensive sheets. These lava sheets were immedi- 
ately subjected to oceanic friction and disintegration. The 
glassy scoria was quickly broken and deposited as sedimen- 
tary material. The occurrence of grains of aporhyolyte in 
this grit shows that in these surface rocks the well known "red 
rock," so called, of the lake Superior region, was an im- 
portant ingredient, and indicates that the traps that underlie 
this conglomerate at Taylor's Falls are structurally compara- 
ble with those associated with the red rock series of the north- 
ern part of the state. Still it is also certain that basic elements 
entered much more extensively into the accumulating con- 
glomerate. The coarser and distinctly boulder-part of this 
stratum is composed almost, entirely of basic material. This 
is to be accounted for by the immediate proximitv of the 
basic traps of the formation which preceded the conglom- 
erate, which afre several hundred feet thick and which rise 
