Fishing Limestone Streams: A Complete Guide to Fishing These Unique Waters
Limestone streams present some of the most intriguing and challenging fly-fishing waters in mid-America, flowing through such storied fishing regions in Pennsylvania, Virginia, West Virginia, and New York. Meck explains what limestone streams are, how they significantly differ from freestone streams, and why they are such an important part of the environment
Here's a nice article by a fly fishing expert on the effect of the geology.
Rich and Poor Trout Streams
by Tom Rosenbauer
Geology determines the entire character of a trout stream. A glance at the surrounding terrain can tell you how big the trout will grow, how much food is available to them, and how they will be distributed in the stream; it also helps you predict their feeding behavior and even what flies will work.
http://midcurrent.com/techniques/rich-a ... t-streams/