48  Pretz: FLorA oF LEHIGH COUNTY, PENNSYLVANIA 
240 m. or occasionally higher, increasing in altitude westward 
beyond the Jordan Creek, where in Lynn Township they receive 
the name of Shochary Ridge, and culminating in the Spitzberg, 
330 m. The effect of these ridges on the drainage of the northwest 
portion of the county is marked. Still farther westward beyond 
the county these ridges rise as high as the Kittatinny Range. In 
general the entire topography of this formation is characterized by | 
a multitude of short valleys and rounded hills, which range in 
altitude from less than 180 m. to the maximum above quoted. 
The average altitude of this “plain,” which it really is, must be 
approximated from these elevations but can be stated at about 
210 m. 
The limestone region in general is about 60m. lower than the 
shale region and is characterized by broad river valleys and more 
gentle rises from the streams to the comparatively even uplands. 
The resulting topography is like a gentle plain in appearance when 
viewed from the South Mountains and differs markedly from the 
rugged shale plain to the north. Inthe vicinity of the streams 
outcrops and rocky talus slopes are present. The soil is charac- 
terized by greater fertility than the colder, moister soil of the shale © 
region and for this reason the region is largely under cultivation. 
The Saucon Valley between the hills of the South Mountain 
range is almost exclusively of limestone formation with a bit of 
shale, originally continuous with the formations of the Kittatinny 
Valley, and is little varied in topography, a lovely valley of mostly 
cultivated land framed by the hills of the South Mountain range. 
On the south the county barely touches the ‘‘red sandstone, 
shale, conglomerate and trap”’ rocks of the Triassic Period of the 
Mesozoic Era. 
The Lehigh River is the largest stream of the county. From 
Lehigh Water Gap to Allentown, where it is deflected eastward 
by a spur of the South Mountain, it flows through the shale and 
limestone country, and a number of cliffllke outcrops and sharp 
rises of talus slope exist as the result of its erosion. 
Several creeks, including Trout Creek, Rockdale Creek, Fells 
Creek, Spring-Creek, and Coplay Creek, drain into it between these 
points, but about five-sixths of the drainage of the county is 
directed toward Allentown, where the combined Jordan Creek 
and Little Lehigh River discharge into the Lehigh. 
