76 The Limestones, and Lime. [Feb., 



The facts which are established in regard to the age of the 

 rocks composing the earth's nucleus, and which w^ere in the main 

 consolidated before the creation of animals, go to prove that they 

 were formed at the same period, but that in after times they have 

 been subjected to certain changes which, in one case, has placed 

 a given mass in a position superior to the others, and other in- 

 stances still, the latter have been placed in a position superior to 

 the former. 



Lime seems to be one of the essential constituents of animals 

 and vegetables; it enters into them as a part of their frame work, 

 and without doubt the provision of this material was prospective. 

 In the earliest sedimentary rocks, it is derived immediately by 

 abrasion of the primary rocks preexisting. When water contains 

 carbonic acid in solution, it is capable of dissolving carbonate of 

 lime. Muriate of lime is very soluble, and sulphate of lime more 

 soluble than the carbonate. In consequence then of the solubility 

 of the calcareous compounds, lime has existed in all waters; 

 largely in some, but in others only in small quantities; hence, it 

 has been brought within the reach of all organized beings, being 

 found not only in the seas and larger fresh water lakes, but also 

 in most soils, from which it is taken by the roots of plants. 



We do not pretend to account for the origin of lime, or rather 

 the original creation of limestone. We merely speak of its 

 derivation, it coexists with the earliest rocks, and has been sub- 

 jected to the same agencies; the great mass in the interior is 

 brought to the surface and ground down like other rocks, and 

 hence it appears as common as sand and clay, in all the forma- 

 tions which are really sediments. Lime, too, exists largely in 

 rocks which are not in the common acceptation of the word cal- 

 careous. Though it cannot be considered a constituent of gneiss 

 and granite, yet it is a constituent of feldspar which enters largely 

 into the composition of those rocks. So it is found in mica; and 

 when we examine the sediments which appear to consist mainly 

 of alumina and silex or sand, still lime is found even there — and 

 if we analyze any of the rocks in the Taconic and Silurian sys- 

 tems, few are found which are destitute of it. It forms 10 per 

 cent very frequently in rocks w^hich are never regarded as calca- 

 reous. The universal distribution of lime and limestone, then is 

 an important feature in our system of rocks and serves a purpose 

 which in the constitution of things is of the greatest moment to 

 animals and vegetables. 



Limestones of the Taconic System. — In the ascending order 

 the Taconic succeeds the primary system; it contains two dis- 

 tinct ranges of limestone, one of which is often magnesian. The 

 strike of the system is north a few degrees east, which brings 

 the limestone ranges on the western side of the primary system 



