670 KANSAS CITY REVIEW OF SCIENCE. 



liar occurrence of the chert beds, which are everywhere quite common, is almost 

 as interesting to the scientist, although they will never call together thousands of 

 people, or transform the poor disheartened prospector into a millionaire. 



The chert formations occur at different depths, as deep as shafts have been 

 sunk, alternating with limestone. In some places there seems to be but little 

 regularity to the deposits, while in others they lie one above the other, the irreg- 

 ularities of the one closely fitting those of the other. A high bluff on the right 

 bank of Shawnee creek, about half a mile above where it enters Spring River, 

 affords a view of these alternations. This bluff is from 80 to 100 feet high, and 

 is very abrupt, making an angle of about 75° with the horizontal. Here the 

 layers of Hmestone and chert alternate with great regularity, the layers of each 

 varying from only a few inches in thickness to as much as three feet. 



In some places there seems to be no opening or crevice between the two 

 kinds of rock, but they are firmly held together so that when the rocks are 

 broken in pieces, fragments may be obtained, consisting partly of limestone and 

 partly of flint. Cart loads of such specimens could be picked up along the foot 

 of the bluff. 



On the left bank of Spring River at the little town of Lowell, is another high 

 bluff, which affords excellent opportunities for studying the formations. Here 

 also are limestone and chert formations alternating with each other. The layers 

 of chert are not continuous as they are at Shawnee Creek bluff. A layer at one 

 place may be six inches thick and at a short distance in either direction entirely 

 disappear, thus presenting somewhat the shape of a very large thin disc. 



Throughout this whole region may be found cherty concretions, having in 

 general the shape of a prolate spheroid, the major axis of which is twice that of 

 its minor. These differ greatly in size. Some of them are so small that the 

 major axis does not exceed three inches, while in others it is fully twenty inches 

 long. These concretions are generally solid throughout; occasionally, however, 

 one is found with a small, narrow cavity at the centre, parallel with its major 

 axis. As far as I have observed, these cavities are never lined with crystals. A 

 transverse section of the concretions shows concentric circular bands, intimating 

 that their formation was symmetrical with reference to their major axis. 'I he 

 miners call them " mineral eggs." I have noticed them in greatest abundance 

 on the west side of the river. On the right bank of Shawnee creek, half a mile 

 above the high bluff before referred to, in connection with other cherty rocks, 

 they occur fully fifteen feet above the highest limestone horizon. (It might 

 properly be stated that north and west of the sub-carboniferous is a great 

 sandstone formation, the limits of which I cannot give, but f think it is bounded 

 on the west by Neosho River and extends some thirty miles north). In a i^^^ 

 instances, these concretions have been found imbedded in limestone which fit 

 closely around them. These chert rocks are filled with fossils, which are so 

 numerous that it is doubtful whether, from the shells alone, a limestone could be 

 distinguished from a chert rock. In fact, almost every fragment that is picked 

 up, is filled with fossils, whether it comes from the hill side or from the gravel 



