80 University Geological Survey of Kansas. | 
object, such as the root of a plant, which was subsequently 
removed, leaving an opening. Such rounded masses are 
variable in size and shape, and frequently are banded in 
structure, showing that concretionary rings differed in color 
sufficiently to make themselves noticeable. They vary in 
size from that of two inches or less in minimum diameter to 
a maximum of two to three feet. These jug-shaped bodies 
are exceedingly abundant on all border lines where the two 
kinds of rock come together, and are now found in great 
abundance in hills composed of residual matter in so many 
parts of the district. In early days miners often spoke of 
them as ‘‘ mineral eggs,’’ which implies that they recognized 
some relation between them and ore bodies. 
Border lines between the flint and limestone by no means 
are composed entirely of concretionary masses, but masses of 
different shapes and of many sizes also are found. The 
‘‘open ground’’ of the miner consists principally of these 
odd-shaped rocks in representative flint masses left behind 
as a residuary mass after meteoric waters dissolved out the 
interbedded limestone, allowing insoluble bodies of flint to 
settle themselves together with all irregularities imaginable. 
Both primary and secondary flint often contain fossils, or 
rather the cast of fossils, from which the calcareous shells 
themselves haye been removed by solution. Also, they are 
full of fractures, the fractures being so numerous and so 
varied that widely different results are produced. The most 
noticeable feature of this is the great abundance of fractures, 
large and small. The writer has repeatedly stated that no 
piece of flint has yet been found from which a cube six inches 
in diameter could be obtained which did not have one or 
more fracture planes crossing it. Such a statement has been 
made to hundreds of different miners and mine operators and 
prizes offered, but to date no such piece has been found. 
The fractures in general are irregular, passing in different 
directions, both vertically and horizontally. But there seems 
to be a great preponderance of vertical seams over horizontal 
ones. In many places the vertical seams have divided the 
rock into long, slender fragments which in a crude way imi- 
tate knife blades. This has given rise to the term ‘‘ butcher- 
