THE BURLINGTON GRAVEL BEDS. 329 



Dr. John Fee, city physician, with whose writings in reference to the eye 

 and color bUndness the pubhc are famihar, writes: "The Hmestone that is 

 broken and placed upon our streets as a macadam has a white, ghttering appear- 

 ance that is quite trying and injurious to the eye. I should regard the chert from 

 the Burlington Gravel Beds as a great improvement to the limestone in its optical 

 effects." 



Dr. T. J. Eaton, chemist of the Kansas City Medical College, writes: "I 

 have examined the sample of chert (or Burlington gravel). It seems to be one 

 of the sub-varieties of the numerous quartz family. It has the colors of jasper, 

 the hardness of flint, but a little more brittle than the latter. Its physical and 

 chemical properties render it one of the best macadamizing agents known. Its 

 hardness would make it durable. Its color is easy on the eye. Its brittleness is 

 just right to make it pack properly on streets that are much used. While mixed 

 with a small proportion of our best limestone, it would pack all right for residence 

 streets, I hope to see a test made of it on some of our streets in Kansas City. 

 If it proves practically what it promises theoretically, and the cost of getting it 

 here is not too great, it will soon supplant the miserable stuff we are now spread- 

 ing on our streets. 



Capt. J. M. Trowbridge, late city engineer of Kansas City, writes : " From 

 such very limited samples of the Burlington gravel as I have seen, I am of opin- 

 ion that the wearing qualities are of the highest order. It is a silicious gravel 

 made up -principally, so far as my limited 'opportunities of observation go, of 

 jasper, and other kindred minerals, differing principally in color though not in 

 texture or in hardness. Besides being hard it is tough, quite as necessary a quality 

 for a pavement as hardness. It resists a shock or concussion as well as it resists 

 abrasion. This quality will be better understood by comparing it with glass. 

 Glass is hard, but it is fragile, reduces to powder easily, and if available, would 

 be unsuited to paving purposes on that account. So with a certain silicious strata 

 in the limestone of Kansas City. It is quite hard, and flinty in appearance and 

 characteristics. It resists the drill, but spoils or chips with the utmost freedom, 

 and would reduce to sand or wear out under the traffic of our streets with great 

 rapidity. The Burlington gravel would do neither. 



'•' Again its general shape, flat and thin, rather than round or cubical, gives 

 it additional value for this purpose. It were easy to show, both theoretically 

 and practically, the value of that form, but I need not lengthen this note for that 

 purpose. 



" There are in my judgment only two questions concerning this material; 

 those are cost and binding, or cohesive qualities. Some gravels, as that at Cape 

 Girardeau, possess this binding property in an eminent degree. Thrown loosely 

 upon a grade, it packs very quickly into a compact solid road-bed. Others 

 though hard and tough fail in this quality, and never give a compact surface. 

 Perhaps this question is already favorably decided by the trials at Burlington, 

 where, I understand, it has been in use for years with satisfaction in this respect. 



