THE GEOLOGY OF THE SYRACUSE QUADRANGLE 45 



supply of water as the strata differ in porosity, but none of the 

 strata in the area are exceptionally good aquifers so that the supply 

 of water from many of the wells is limited, yet for the most part 

 sufficient for household and farm purposes. 



Deep wells in the middle portions of Onondaga valley will get 

 salt water similar to that in the wells at the east end of Onondaga 

 lake. 



THE PERIDOTITE DIKES OF SYRACUSE AND VICINITY ' 



There are several localities in central New York in which dikes 

 of basic rock cut through the Paleozoic sedimentaries. There is 

 such a dike in the city of Syracuse, one at the Dewitt reservoir, 3 

 miles east of the city, another near Otisco lake, some 15 miles south- 

 west of the city. Other dikes somewhat similar to these are known 

 to occur near Itahaca farther to the southwest and at Manheim 

 farther to the east. 



The occurrence of these dikes in the midst of the great area of 

 Paleozoic sediments far removed from any volcanic or batholitic 

 areas have naturally aroused considerable interest. The Syracuse 

 dikes are here described, brief notice is taken of the other localities, 

 and the bibliography aims to cover all the literature available relating 

 to the different dikes. The literature of the subject is listed chrono- 

 logically at the end of the chapter and numbered serially. Reference 

 to these papers in this chapter is given by the serial number. 



HISTORICAL 



The Syracuse peridotite dike, commonly known as the Green 

 Street dike, was discovered in 1837, ^y the late Professor Oren Root 

 of Hamilton College, at that time principal of the Syracuse Academy. 

 He recognized the rock as a serpentine and brought it to the atten- 

 tion of Lardner \'anuxem who was then engaged upon the geologi- 

 cal survey of the Third District. Vanuxem's description of the 

 dike in his report on the Third District of New York, 1839 (i), 

 is the first mention of it in geological literature. He there says: 

 " The green and traplike rocks observed near the top of the hill to 

 the east of Syracuse, haye been examined so far as time would 



' Much of the material for this chapter was collected hy Burton \V. Clark 

 and presented hy him in a thesis for the M.S. degree at Syracuse University 

 in HJ08. The dikes near Clintonville were discovered after his thesis was 

 written. 1 am resi)onsil)le for the form and arrangement as here presented. 

 T. C. H. 



