14 BULLETIN OF THE 



Later, Di*. J. J. Bigsby, while considering the Huronian as distinct 

 from the Cambrian, still referred the rocks of this district to the Hu- 

 roniau.* 



In the "Geology of Canada," 1863, these rocks are taken as Huro- 

 nian (p. G6). The rock at Presque Isle was classed as a cedimentary 

 serpentine belonging to this formation by Dr. Hunt (pp. 472, 595) ; 

 taking his analysis from Professor Whitney's work,t who regarded it as 

 closely related to serpentine. 



Dr. Hunt states also that the great beds of red hematite are strati- 

 fied (p. 596), and he considers their deposition as proof of the presence 

 of vast amounts of organic matter at that day (p. 573). 



Dr. J. P. Kimball, under date of December 19, 1864,:}: remarks : " My 

 own observations in the Iron region impressing me with the indigenous 

 character of the larger masses of diorite and granite represented within 

 the defined area of the metamorphic strata, and their entire distinctness 

 from intrusive dikes or erupted masses, and concurring in the recog- 

 nition of these strata by Mr. Murray as Huronian, I am disposed to 

 regai'd the entire region as of metamorphic character, all of whose larger 

 masses of crystalline rocks are indigenous, and to be divisible into the 

 two formations, Laurentian and Huronian : the former formation proba- 

 bly forming the surface of the areas known as the granite ranges, while 

 the latter probabl}^ occupies, with minor deviations, the limits laid 

 down for the crystalline schists comprehended under the name Azoic." 

 (I. c, p. 293.) " Possessing the same stratigraphical conditions as the 

 schistose rocks, while many varieties of them are represented in the 

 schists by their exact counterpart as to composition, the crystalline 

 Huronian rocks must be regarded as essentially metamorphic, while in a 

 comprehensive view of the whole series it is seen that together with 

 variable conditions of deposit, it indicates variable degrees of local meta- 

 morphism. Plentiful evidence exists of the blending of a rock of one 

 character into that of the other, or the continuity between crystallized 

 and schistose beds Besides the indigenous crystalline rocks dis- 

 tributed throughout the Huronian series, exotic or intrusive crystalline 

 rocks are met with, but only in the form of dikes, and limited to a nar- 

 row distribution." (L c, p. 295.) " It may not be inappropriate to 

 suggest the pi'obability that the larger and more persistent bodies of 

 gi"eenstone bearing approximately east and west — that is, conformably 



* Quart. Jour. Geol. Soc, 1863, XIX. 36-52. 



t Am. Jour. Sci., (2,) XXVIII. 18, 1859. 



t Am. Jour. Sci., (2,) 1865, XXIX., 290-303. 



