THE GEOLOGY OF THE SYRACUSE OUADIL\NGLE 47 



and some portions of the calcareous rocks have become crystalline 

 and are filled with crystals of celestite and calcite, while other beds 

 are converted into a calcareous ophiolite. ... I found a portion 

 of this ophiolite in powder to be readily attacked by acetic acid, 

 which dissolved a large amount of carbonate of lime, besides a little 

 magnesia, and traces of alumina and iron. The analysis of the ser- 

 pentine gave me: silica 40.67; magnesia 32.61; protoxyd of iron 

 8.12; alumina 5.13, and water 12.77." 



So far as known, this is the first analysis made of this rock. 



Doctor Hunt describes this rock as metamorphic. He says : 

 " Ophiolites have generally been regarded as intrusive rocks. In 

 southern Europe they occur in injected masses traversing the dis- 

 rupted nummulitic strata, but they are also found in the same region 

 interstratified with limestones, and with micaceous, chloritic and 

 talcose schists which are regarded as altered Triassic strata. In 

 North America the ophiolites of the Laurentian, Silurian and De- 

 vonian formations are all apparently magnesian sediments which 

 have been metamorphosed in situ and never so far as I am aware 

 assume the form of intrusives. ... I have already shown that 

 the action of a solution of alkaline carbonate at a slightly elevated 

 temperature upon mixtures of earthy carbonates and quartz suffices 

 to convert the bases of these into hydrous silicates. The same agent 

 has at the same time given rise to the feldspar and mica of the 

 associated strata." 



George Geddes (5) in his Report on the Geology of Onondaga 

 County in i860 described the dike rock as follows: '* There are 

 two masses of this vermicular rock, one low down, of about 20 

 feet in thickness, appearing on James street, Syracuse, and at various 

 other places ; the upper mass is thinner but its thickness is not uni- 

 form. In the lower mass on James street, are some specimens of 

 crystalline character, being serpentines, the action of crystallization 

 having been very powerful but local, producing mica, and even 

 nodules of granite, or rather syenite." 



The next mention of the dike was by Dana in the second edition 

 of his Manual of Cieology, 1875, (6) in which he says: "Near 

 Syracuse, there is a bed of serpentine in this formation (Salina), 

 along with whitish and black mica, and a granitelike rock, in which 

 hornblende replaces the mica, making it a syenite ; there is little 

 evidence of heat in the beds adjoining these metamorphic rocks. 

 (The position of this locality is not now known)." The same state- 

 ment is made in the third edition but omitted from the fourth edition. 



