SURFACE GEOLOGY. G 5 . 29 



At the heads of Choconut and Apolacon creeks similar 

 low Drift-filled divides are seen separating their waters from 

 those that go southward into the Wyalusing. 



The Soils of the region. 



The soils of the district have been largely derived from 

 the decomposition of rocks in situ, since the hill slopes are 

 generally so steep that the Drift is seldom found remaining 

 on them except in scattered patches. 



Since the CatsJcill system furnishes almost all of the sur- 

 face rocks in this district, the soils have been largely derived 

 either from their gradual decay or trituration by glacial 

 action. 



The red shales of the Catskill have probably contributed 

 more to the formation of the soil than any other part of it, 

 and it is the universal testimony of the farmers that the 

 ''"red shale soils'' are generally stronger and richer than 

 any others. 



A sample of the Cat skill red shale which forms the basis 

 for so much soil in the district was forwarded to the labora- 

 tory of the survey at Harrisburg and analyzed by Mr. 

 Stinson with the following result : 



Silica, 59.260 



Alumina, 19.877 (by deduction.) 



Sesquioxide of iron, 10.071 



Lime, 0.250 



Magnesia, 1.917 



Sulphuric acid, 0.012 



Phosphoric acid, 0.158 



Water, 3.600 



Alkalies, 4.855 



The amount of alkalies in the shale doubtless accounts for 

 the fertility of its soil, since the quantity of lime and phos- 

 phoric acid is not sufficient to have any marked influence for 

 good. 



But while the red shale soils are usually the best in the 

 district it is equally true that only in isolated patches and 

 in favorable localities do we find any really first class soils 

 within the district. The great body of the surface is covered 

 by a thin sandy soil of very little natural fertility, and ex- 



