18 STEATIGRAPHICAL GEOLOGY. 



tremeljf slow, so slow, that a foot may represent a thousand j'ears, or even more. 

 The shales, clays and marls may have been deposited with greater rapidity; but 

 when wc eonside)-, that the change from one kind of rock-forming material to an- 

 other indicates a, l)rcak in tlie continuity of time, and that great lapse of time was 

 necessary for the growth of the marine and land vegetation, which formed the coal 

 found between beds of c]:iy and shale, wc arc led to the conclusion, that the time 

 which elapsed licbvccu two separate beds of clay and shale, or marl, added to the 

 time necessary foi- the ilcposition of their matei'ials, will, on the whole, make their 

 formation as slow as that of the limestones. The sandstones and conglomerates, 

 particularly those of the Com! :\Ieasures, seem to ha\-c been made up of trans- 

 ported materials, and were therefore <lei)ositcd much faster than the limestones, 

 though but few of them appear to have been made with any rapidity. The even- 

 ness of the strata, over a great extent of country, indicates slowness in trans- 

 portation and deposit. The i';irt. that the materials must have been taken from 

 pre-existing rocks, by the \yater, before transportation, tends again to convince us 

 of the slowness of their formation. From these considerations, it would not be 

 extravagant to say, that palteozoic time reiiresents more than one hundred millions 

 of years, and we would close our eyes against the testimonj' of the rocks, were we 

 to conclude that palteozoic time could be estimated by years less than many 

 millions. 



The vegetable kingdom began with the lowest of it^ kind, the algse or sea 

 weeds, and with the lowest forms of these. The development was as gradual as 

 the deposition of the strata. It was not until the Devonian age, that land plants 

 appeared of sufficient firmness for preservation, if we except Dawson's Psihjphijton^ 

 which probably grew in a marsh. These were of the lowest classes. They be- 

 came more diffuse and diversified with the lapse of time ; but the palseozoic era 

 closed without the appearance of anj' of the higher orders or classes. 



The animal kingdom likewise began with the lowest of its kind, the E<jzoon 

 caniidense. The learned Dr. Haeckel has established the fifth sub-kingdom in 

 animal life to include forms below the llmlhitu, and therefore y^^ry nearly related 

 to inorganic matter. This suli-kingdom he has called Prollnla. The Eo-ann 

 (•aiiiiflcnse, under this classification, belongs to the order PnhiUKiUniua, sub-class 

 Jiadiolaria, class JlJti~opi}il<i, sub-kingdom Protista. Ages passed, about which 

 we know very little, before the period of the St. John's Group, which ushered in 

 the lower Silurian. At this time wc find the lowest forms of the Radiates, ^[ol- 

 lusks and Articulates. The Articulates are represented by the lowest fcums of 

 theTrilobites, which, in their perfect state, i-epresented the embryonic condition 

 of the existing X/);(/'/».s. Millions of years pass l)y again, before the appear- 

 ance of Gasteropoda, and Cephalopoda, in the Upper Potsdam Group; meantime 

 the system of life, which commenced with the lowest forms, as if by spontaneous 

 generation, by evolution, increases species and genera and reaches a higher and still 

 higher grade of developmeut. Later still, in the Calciferous Group, the LcnneUi- 

 hrunchi'itn commenced its existence; a class that has fought its way throuo-h all 

 succeeding time, and is even now in the height of its prosperity and advancement. 

 All classes of life, which existed in the ocean, up to the first appearance of the 

 Lamellilir((i)chiiita, continued to live, devi4op, increase their species and genera 

 and improve, through millions of years, before the 'Vertebrates first made their ap- 



