294 'I^li(^ Afnerican Geologist. November, i899 
ments in Morrison county, Minnesota, I desire to emphasize 
the fact that anything like a finished implement is exceedingly 
rare, even in the large "pockets" of chips on the Modern flood- 
plain close to the outcropping quartz veins. During my re- 
searches I did not find a single piece of quartz showing the 
least trace of any definite form such as might indicate the na- 
ture of the implement which it was proposed to fashion from 
it. Nearly all the fragments were small and evidently mere 
refuse, not of the finishing shop, but of the first manipulation 
of the rock after it left the "quarries." Some, indeed, appeared 
to show evidence of the marginal secondary chipping, but they 
were mere flakes, and the evidence probably deceptive. In a 
few cases forms were observed which might, by a stretch of 
the imagination, be conceived of as belonging to a palaeolithic 
type, but they occurred as parts of the ordinary refuse, and 
were mere accidents of manufacture. 
Dec. ig, i8g6, Frecport, Illinois. 
ON STRATIFICATION PLANES. 
By Charles R. Keyes, Des Moines, Iowa. 
The layered structure of sedimentary rocks has long been 
regarded as their most characteristic feature. To the surfaces 
along which splitting is most apparent, the term bedding 
planes is generally applied. In the treatises on stratigraphy 
the layered arrangement in rock masses is considered altogeth- 
er from the standpoint of a purely structural character. Bed- 
ding planes are dismissed as only very local phenomena. The 
text-books on geology seldom give hint of any possibility of 
Ijedding planes not having the same stratigraphical value. 
Statements regarding the laminated characters of the rock 
usually distinguish only those kinds that are liable to be mis- 
taken for those resulting from causes other than sedimentation. 
That stratification planes may have quite different values 
in geological work, and that they actually do often have a vari- 
able significanc'e is manifest from even the casual perusal of 
most published works relating to stratigraphy, notwithstand- 
ing formal statement is wanting. 
