422 METAMORPHISM. 



dolomite, according to the analysis of c. H. H. in his Report. When polished we perceive 

 that the harder parts were broken up into angular fragments, mostly of the red parts, which 

 look as if they wei'e disseminated through a tenacious paste. The white or crystalline 

 parts of the stone have taken the form of very irregular jagged veins in which the red 

 angular fragments, sometimes nearly dissolved, seem to float as the fragments of ice in a 

 river in a winter's flood. The brecciated dolomitic (Hunt) marble of Plymouth, with a 

 dark base, contains a vast number of elongated fragments of compact limestone, though it 

 does not so clearly prove a plastic condition as the Winooski marble. We regret exceed- 

 ingly not being able to give a sketch at least of this latter rock. But we have not pecun- 

 iary means for even one wood cut more. We hope, however, that the citizens of Vermont 

 will patronize the Winooski marble enough to obtain at least a table top, and they will 

 then have before them (though this is true of only one variety) a much better exhibition 

 of these interesting phenomena than a photograph could give. 



The simplest form in which limestone begins its course, is that of rrfarl found in the 

 bottom of ponds deposited from the water, and of which beds are marked upon the Map 

 of Surface Geology. They consist, as fully explained elsewhere, of carbonate of lime in 

 the form of powder, with clay and numerous little shells. This at length may be con- 

 solidated by the same substance held in solution, and thus it becomes a soft rock. The 

 water may hold in solution, also, iron and silica, and perhaps carbonate of magnesia, and 

 these also become solid ; and we have compact silicious limestone, perhaps with magnesia ; 

 or this last ingredient may be in so large quantity that the rock becomes dolomitic, that is, 

 it has more than 40 per cent, of carbonate of magnesia in it. Thus far the rock does not 

 show much of crystallization, though often traversed by veins of calcareous spar, filled by 

 the deposition from water. It is also more or less colored, and may have a dirty aspect. But 

 up to this point no great degree of heat is necessary. Suppose now by the upward per- 

 meation of heat, hot alkaline water penetrates the rock. " The organic substance (by 

 which the color is produced) is gradually removed by water, while carbonate of lime is 

 deposited in its place. If this displacement was complete, white granular limestone would 

 be produced : when not complete, gray limestone would be produced. In this manner 

 the origin of the gray streaks, veins and spots, is quite intelligible. In the conversion of 

 sedimentary limestone into granular limestone the fossils are generally quite obliterated" 

 (Bischof.) " 



The enormous development of white limestone in the Eolian formation, is a magnificent 

 example of the metamorphosis above described. On Mt. Eolus and Danby Mountains 

 alone, to say nothing of Rutland, one would think there is marble enough to supply the 

 whole country till the Millennium ; and if more should be wanted during that period, we 

 think Equinox, Anthony and other mountains to the south would supply the demand. 

 The counterpart to this formation in Europe is the Carrara marble. Whether the beds are 

 as thick as in Vermont we know not ; but the quarries have been wrought since the time 

 of Julius Csesar, and 1200 men are now employed in them. The resemblance between the 

 Carrara marble and that from Eolus, has already been referred to, and it is surely close 

 enough to infer that whatever changes the Carrara rock has undergone have passed over 

 the Eolian. Now the following facts in regard to the Italian rock have recently been 

 ascertained, which we give in the language of Bischof : 



