THE GEOLOGY OF THE SYRACUSE QUADRANGLE 29 



area. They consist of a mixture of clay and the carbonates of 

 Hme and magnesia in about the right proportions to make a strong 

 quick-setting hydrauhc cement when burnt and ground. In port- 

 land cement the materials are mixed by man ; in the waterlimes the 

 mixing was done by nature in the deposition of the materials. The 

 Manlius waterlime has been quarried and used in this area for 

 nearly a century. It was first used extensively in 1821 in the con- 

 struction of the Erie canal through this county. Owing to the 

 great expense involved in removing the overburden the quarries 

 are generally small and do not extend far back from the outcrop 

 of the stone, but the quarries are numerous and form an almost 

 continuous line across the quadrangle and beyond. The largest 

 quarries are near Jamesville, Fayetteville and Manlius and the 

 mills for grinding the cement are located in or near these villages.^ 

 Quicklime for local use has been produced at many different 

 points along the limestone outcrop. Both the large continuous 

 kilns and the smaller intermittent kilns have been used for this 

 purpose. The best quicklime is obtained from the blue Manlius, 

 Helderberg and Onondaga limestones. The production of both 

 the lime and the cement has nearly ceased in this area at the present 

 time. 



GRAVEL AND SAND 



Gravel and sand are now used in ever increasing quantities in 

 construction work, not only in mortars and masonry, but also in 

 concrete in the foundations for buildings, roads and different engi- 

 neering operations. The largest and best supplies of these materials 

 are taken from the postglacial terraces which extend for miles 

 along the sides of the Onondaga valley in and south of the city. 

 Many pits large and small have been opened in these terraces on both 

 sides of the valley. In some places sand alone is obtained, in other 

 places gravel, and sometimes the sand and gravel occur together 

 and are separated by screening at the pit or at the place where it is 

 used. Besides the terrace deposits, there are vast quantities of 

 both sand and gravel underneath the floor of the valley. The Onon- 

 daga valley has been filled in to a depth of several hundred feet and 

 much of this filling consists of sand and gravel. Numerous pits 

 have been opened in various parts of the city from which these 

 materials have been taken out. 



' I'^or further particulars sec 4(;th Kept, of N. V. State Mus.. 1895, P- 237-315. 



