56 ROCK-METAMORPHISM. 



partially rounded or entirely shapeless a peculiarity which Mac- 

 culloch conceived to have resulted "from an incipient solution." 



Nanmann next drew attention to the rounded form of the 

 crystalloids of augite and other minerals in calcitic rocks, par- 

 ticularly in that at Pargas, in Finland, and attributed it to 

 partial fusion. 



Emmons, in 1842, referred to the rounded outlines of crystals 

 of certain minerals imbedded in the crystalline limestones of 

 Rossie, New York, and suggested that they were due to a 

 partial fusion *. 



In 1863 Sterry Hunt briefly noticed the occurrence of rounded 

 grains of various minerals in the Archaean rocks of Canadaf- 



Our attention having been drawn to the so-called ' c chamber- 

 casts of Eozoon " in 1866, we identified them with the crystal- 

 loids in the hemithrenes of Pargas, Tiree, and New Jersey, also 

 with the lobulated grains of serpentine common in the ophite of 

 Connemara. It was likewise suggested by us that they had 

 been shaped by chemical reactions aided by heated water, which, 

 having affected them superficially, had removed their substance 

 and replaced it by the calcite in which they are now imbedded J. 



About the same time as ourselves Giimbel noticed similar 

 rocks, also the peculiar form of the crystalloids contained therein; 

 but he adopted the view, then pretty generally received, that 

 the latter were of organic origin . 



In his report, addressed to Sir William E. Logan, and pub- 

 lished in 1866, Sterry Hunt, again referring to the subject ||, 

 drew attention to the fact that crystalloids with rounded forms, 

 besides occurring in the bedded hemithrenes of Canada, are also 

 present in "calcareous veins " (some being 150 feet thick) 

 intersecting the latter and the associated gneisses, dolerites, 

 &c. As this fact will have to be noticed again, its further 

 consideration may for the present be deferred. 



* Geology of the First District of New York, pp. 37-39. Delesse, we are 

 aware, lias noticed rounded crystals ; but, unfortunately, our extract, stating 

 the fact, from one of his memoirs has got mislaid. 



t Report, Geological Survey of Canada, 1863, p. 592. 



$ Quart. Journ. Geol. Soc. vol. xxii. pp. 198, 199, 209 (Jan. 1866). 



Sitzungslberichte d. Miinchener Akad. d. Wissensch. (Jan. 1866). 



|| We find no reference to the rounded crystalloids in S. Hunt's memoir 

 " On the Mineralogy of certain Organic Remains from the Laurentian Rocks 

 of Canada," published in the Quart. Journ, Geol, Soc, vol. xxi. (Nov. 1864), 



