214 PEOCEEDINGS OP THE (GEOLOGICAL SOCIETY. [Jan. 10, 



grained"*. The Delaware Ophite has indisputably the essential 

 characters of the type rock ; and, considering that its locality lies 

 somewhat in the direction of the strike of the " Quebec series " in 

 eastern Canada, there is some probability of this variety being 

 systemally contemporaneous with the former. 



The Connemara Ophite is considered to be Lower Silurian by Sir 

 Roderick Murchison and Professor Harkness ; but there are reasons 

 which weigh with us, as already stated, in assigning it to the Lower 

 Cambrian period. With regard to the varieties from India and 

 Bavaria, we are unable to offer any opinion as to their geological 

 age. A " remarkable " Ophite, occurring in the Devonian system 

 at Syracuse in the State of New York, is described as consisting of 

 an " aggregation of grains," — a character which leads us to infer 

 that it is " eozoonaP't. The Isle-of-Skye Ophite, which unmistake- 

 ably possesses the leading features of the Grenville type, brings us to a 

 much more recent systemal period, it being no other than Liassic ! 



The fact of " eozoonal rock " being a member of various Lower 

 Primary systems is enough to throw considerable doubt on its pre- 

 sumed organic origin. The Devonian example at Syracuse, if it 

 be of the same kind, is a still greater stumbHngblockj:. But how 

 are we to explain the presence of '^ eozoonal " Ophite among the 

 Liassic saccharoid marbles of Strath, in the Isle of Skye§ ? The bare 

 fact of the existence of such a rock, separated as its epoch is by 

 several vast systemal periods from that occurring at Grenville, must 

 be regarded as a conclusive argument against the view we are op- 

 posing. But when it is considered that the so called " Eozoon " has 

 never yet been found except in metamorphic rocks — that there are 



* See ' Geology of Canada,' 1863, pp. 248, 266, 611, and 824. The Laurentian 

 or Grenville Ophite appears, in comparison with that belonging to the " Quebec 

 series," to occur on a much less extensive scale, forming very subordinate portions 

 in masses Of pyroxene, and zones of limestone (op. cit. p. 25 ; Quart. Journ. 

 Geol. Soc. vol. xxi. p. 50, &c.). Even the Connemara Ophite seems to be more 

 abundantly developed and less fragmentary than the latter. 



t See Vanuxem, ' Geology of New York,' vol. iii. p. 109 ; also ' Geology of 

 Canada,' 1863, p. 635. 



\ If this Ophite is an "example of local metamorphism," and it possesses 

 " eozoonal " structure, it may be held as another geological evidence totally sub- 

 versive of the organic origin of the Grenville rock. 



§ It is only fair to mention that Professor Harkness, to whom we are indebted 

 for a specimen of the Isle-of-Skye Ophite, first brought this point under our 

 notice, when he was with us in Connemara. But at that time, although Dr. 

 Maculloch, as far back as 1819, had expressed himself " inclined to attribute 

 the whole metamorphism of the Liassic beds of Strath to the influence of 

 the Syenite " with which they are in contact (see ' Western Isles of Scotland,' 

 vol. i. p. 331), we entertained considerable doubts, countenanced by Sterry Hunt's 

 opinion that the hypersthenites around Lough Coruisk belong to the Upper 

 Laurentian or Labrador system (See Silliman's Journal, 2nd ser. vol. xxxvi. 

 p. 226), of the metamorphosed beds above noticed being Liassic. Now, what- 

 ever may be the age of the neighbouring hypersthenites, all our doubts have been 

 dispelled regarding the chronology of the saccharoid marbles, and their included 

 layers of Ophite, after reading Geikie's paper " On the geology of Strath, Skye," 

 as this author, with Dr. Wright's palaeontologieal assistance, has clearly shown 

 them to be altered limestones, shales, and grits of the Liassic period (See Quart. 

 Journ. Geol. Soc. vol. xiv. pp. 1-36). 



