94 



GEOLOGICAL KECONNOISSANCE 



SECTION OF BOAT MOUNTAIN— Continued. 



I 8 



S S 



I ■ 



I 8 | 



8 I 



CL | CL 



60 



Coarse-textured and subcrystalline mem- 

 bers, etc. — Continued. 



Sandstone. 



ing character of the sur- 

 face, together with the 

 interspersed groves of 

 timber, break the other- 

 wise monotonous ap- 

 pearance of some of those 

 prairie scenes. The prai- 

 rie soil, both of the Mar- 

 shall and Huzza prairies, 

 is derived in part from 

 the disintegration of the 

 subcarboniferous lime- 

 stone, sandstones, and 

 shale of the preceding 

 section, and in part of 

 the cherty limestone on 

 which it is based. Where 

 the soil is mostly, or ex- 

 clusively, derived from 

 the latter, it usually pro- 

 duces land supporting 

 stunted oaks, less rich 

 than the preceding soil, 

 and not so well adapted 

 for wheat, but excellent 

 for oats. 



The descent from Mar- 

 shall's prairie to Crook- 

 ed creek, is 230 feet, most- 

 ly over chert derived 



from the equivalent of the light-grey cherty limestone, that underlies the 

 black bituminous shale, at the base of the Boat mountain. Between 

 Marshall's and the Huzza prairies, 100 to 200 feet of sandstone was passed 

 over, interstratified amongst the limestone. 



The ascent from the Big spring, on Crooked creek, to the Baker prairie, 

 is 270 feet. The light-grey limestone is here again exposed with segre- 

 gations of chert, and with some encrinites imbedded ; but the species were 

 not distinguishable. 



One and a half miles south-east of Charles Hutchison's farm, the 'fol- 

 lowing succession was observed in a ravine : 



40 



CL 



Black bituminous shale with segregations 

 and septaria. 



Light grey cherty limestone. 



Sandstone. 



