574 ERA OF MIND. 



and of God ; the first, therefore, capable of conscious obedience or 

 disobedience of any moral law, and the first subject to debasement 

 through his appetites and a moral nature. 



There is in Man a spiritual element, in which the brute has no 

 share. His power of indefinite progress, his thoughts and desires 

 that look onward even beyond time, his recognition of spiritual 

 existence and of a Divinity above, all evince a nature that par- 

 takes of the infinite and divine. Man is linked to the past through 

 the system of life, of which he is the last, the completing, crea- 

 tion. But, unlike other species of that closing system of the past 

 (significantly the Zoic era of geological history), he, through his 

 spiritual nature, is far more intimately connected with the opening 

 future. 



I. Rocks: kinds and distribution. 



The following are the formations of the age of Man : — 



1. Of mechanical origin. — (a.) Marine. — The extended flats 

 which border many coasts, as from Long Island to Texas, and be- 

 yond, and which are now gradually widening the area of the conti- 

 nents ; and deltas, which are similar in general character, but are 

 formed about the mouths of rivers. — Sea-beaches. — Sand-drifts or 

 dunes in the vicinity of the ocean, (b.) Continental. — Alluvium of 

 the lower river-flats ; and, in case a region has undergone elevation 

 during the age, that at higher levels. — Alluvium along the shores 

 of lakes ; and, where, through the modern opening of barriers or 

 other cause, the waters have diminished their height, deposits 

 above the lower plain. About large lakes, different formations 

 analogous in every respect to the Marine above mentioned, except 

 in having no marine relics. — Glacier drift or boulders and gravel, 

 similar to that of the true Glacial epoch, though of more local dis- 

 tribution. 



2. Of organic origin. — (a.) Marine. — Coral reefs, often of vast ex- 

 tent. — Shell deposits, (b.) Continental. — Peat beds, or swamp forma- 

 tions of vegetable character, consisting largely of growing moss in 

 temperate and colder climates, and of diminutive turf-making 

 flowering plants in Alpine and Arctic regions. — Shell beds or shell 

 marl. — Siliceous infusorial deposits. 



3. Of chemical origin. — Calcareous deposits called Travertine, de- 

 rived from calcareous waters, in some cases scores of feet in thick- 

 ness. — Stalactites and Stalagmites of similar form and origin in 

 caverns. — Bog deposits of ore called Bog ore. 



4. Of igneous origin. — Lavas and tufas of volcanic regions. 



