Although dikes in the region about Ithaca have been known for many years, neither extended petrographie study of them nor reliable chemical analyses have been published. In view of the unusual nature of the rock and the isolation from other igneous intrusions, a somewhat more detailed investigation of the occurrence of these dikes and their chemical and mineral composition seemed desirable. The results of this investigation are presented in greater detail in a thesis deposited in the library of Cornell University.
The first known record of the igneous intrusions in the small area under consideration is that by Vanuxem35, 36 concerning the dikes at Ludlowville. The dikes at Syracuse and in East Canada Creek, near Manheim, were noted at about the same time.
J. F. Kemp14 recognized the rock of the Ithaca dikes as altered peridotite similar to that from Syracuse, described by G. H. Williams40 . . .