18 Kansas Academy of Science. 



1. Potamography, 



2. Stratigraphy, 



3. Paleontology, 



4. Economic Geology, 



and shall do so with as much brevity as is consistent with definiteness of statement. 



1. Potamography. 



Norton county has three principal streams, which pass through it in a direction nearly 

 parallel to each other, viz., from the west to the north of east. They all enter from De- 

 catur county, the Sappa, the northern stream, entering within two miles of the northwest 

 corner of the county, and crossing the northern line into Nebraska about eleven miles 

 from that point. Prairie Dog creek enters at the southwest corner of town three, passes 

 through all the five ranges, and enters Phillips county at the northern line of town two. 

 The North Fork of the Solomon river is the most southern of these streams, and it has 

 rather less northing in its course than either of the others, its exit into Phillips county 

 being less than five miles further north than its entry from Decatur. Its course is en- 

 tirely in town five through each of the ranges. The tributaries of all the three streams 

 are but small creeks which cut deep ravines into the body of the high prairie which 

 separates the three valleys. The tributaries of each of the three main streams are longer 

 on the northern than on the southern side of the basin, which means that the main 

 streams are situated nearer to the south than to the north side of their drainage areas. 

 A glance at the map shows this. Connected with this fact is this other, that the slope 

 of the divide towards the northern stream is steeper and more abrupt than the slope to- 

 wards the southern one. These facts are true also of neighboring counties, and also of 

 streams in more distant parts of the State, and also in regions far removed from our 

 State boundaries. The same facts of the stream seeking the southern side of its trough, 

 and the steep escarpments of that southern side, are true also of many short tributaries 

 of tributaries in Norton and other counties. For the explanation of this we must seek 

 not merely to understand the effects of recent erosion, but go back to continental if not 

 terrestrial causes operating in the ages we call geologic. 



In the absence of any regular survey, it is difficult to form estimates of the relative 

 elevation of the beds of these main streams, yet it is generally believed in the county, by 

 intelligent persons, that the valley of the Prairie Dog is higher than that of the Solo- 

 mon, and that of the Sappa than either of the others. Also, that the divide north of 

 each stream is higher than that on the south; i. e., there is a general increase of eleva- 

 tion of the surface northward. The direction of the streams is proof that it also increases 

 westward. The Central Branch U. P. Ely. runs up the Solomon Fork as far as Lenora. 

 The report of its engineers, kindly furnished by Superintendent Fagan, enables us to es- 

 timate the westerly ascent. The difference of elevation between Edmund and Lenora 

 is 156 feet, which gives an increase of about 14 feet to the mile. The elevation northerly 

 is not much less, that of Prairie Dog valley being probably 150 feet higher than that of 

 the Solomon, and that of the Sappa from 80 to 100 higher than that of the Prairie Dog. 

 This fact has a bearing which will be noticed further on. The exact figures which de- 

 termine the full value of that bearing, can only be arrived at by a survey with instru- 

 ments of precision. 



The final fact of the Potamography of Norton county is, that the valleys are all valleys 

 of erosion. Every depression below the level of the highest of the high ju'airie i s due to 

 the erosive action of water, aided by those agencies of varying temperature, force of wind, 

 and other things we include under the term weathering. This erosion lays bare the face 

 of the rocks in the ravines, and the study of it gives us the information necessary to il- 

 lustrate our second head, viz. : 



2. Stratigraphy. 



We recognize in Norton county six distinct strata, two of which belong to Niobrara 



