162 University Geological Survey of Kansas. 
would do just as well were they equally porous. In the great 
Trenton limestone pools the productive rock is a limestone. 
Here, however, nature has performed differently from the or- 
dinary, and by a system of metamorphism has altered the Tren- — 
ton limestone, making it into a rock as porous as many sand- 
stones. Likewise, a shale-bed, if sufficiently compact, may, by 
earth movements, have fissures produced in it which become 
productive reservoirs. Soft shale cannot be productive to any 
considerable extent because fissures produced in it will not re- 
main open, and therefore the necessary underground reservoir 
would not be obtainable. But where shale-beds have been 
metamorphosed and hardened they may become productive, 
provided other necessary conditions obtain. This is illustrated 
notably at Florence, Colo., and in different places throughout 
the California oil-fields, where heavy shale-beds have been 
metamorphosed and fissured and filled with oil. 
Seven colored geological maps are herewith included, cover- 
ing seven different counties, on which the several areas occu- 
pied by the different geological formations are represented in 
appropriate color and design. In studying the detailed geology | 
of eastern Kansas one should examine these maps with care in 
connection with plate III, an ideal vertical section of the Kan- 
sas Coal Measures; plate VIIa, VIIb and VIlIc, a surface map 
in which limestone outcroppings alone are marked in appro- 
priate colors; plates VIII to XIII, inclusive, which represent 
vertical sections across the east end of the state in different 
directions, and, finally, the various plates showing records of 
wells drilled in the oil-fields, which well records are here repre- 
sented in as great number as seems at all desirable in order 
to give a complete exposition of the entire underground condi- 
tions of this portion of the state. The counties represented by 
the colored maps are as follows: Plate XIV, Montgomery 
county; plate XV, Neosho county; plate XVI, Allen county; 
plate XVII, Miami county; plate XVIII, Chautauqua county ; 
plate XIX, Wilson county, and plate XX, Woodson county. 
At first glance the reader unaccustomed to such maps may 
think they are confusing, but a little care will bring everything 
out in a clear manner. The line of demarcation between the 
more prominent formations is indicated by a black line. For 
some of the lesser ones, however, no line whatever is drawn, 
the boundary line being implied by a difference in the colored 
shading. One should think of each individual formation as be- . 
