18 STEATIGRAPIirCAL GEOLOGY. 



tremel3' sloiv, so slow, that ;i, foot inaj^ represent a thousand years, or even moi-c. 

 The shales, elays and marls may have been deposited with ijjreater rapiditj'; but 

 Avlien we eoiisidei', lliaf the ehan^e from one kind of loek-i'orming material to an- 

 other indicates a hreak in tlie continuity of time, and that great lapse of time was 

 nee<>ssar\- for the growtli of the marine and land vegetation, which foi'ined the coal 

 found betwe^■n beds of clay and shale, we are leil to the conciusiou, that the time 

 which elnpsei! between two separate beds of clay ami shale, or marl, added to the 

 time necessary for the dcimsition of their mateiials, will, an the whole, make their 

 formation as slow as that of the limestones. The sandstfines and eongloraei'ates, 

 particularly those of the Coal ^leasutes, seem to have been made up of trans- 

 ported m.'iterials, and were therefore deposited much faster than the limestones, 

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

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

 portation and de|iosit. The fact, that the mnterials must have b<'en taken from 

 pre-existing rocks, by tlie water, before transportation, tends again tf) convince us 

 of the slowness of their foj-mation. From these considertitions, it would not be 

 extravagant to say, that paheozoic time represents more than one hundred millions 

 of years, and we would close onr eyes against the testimony of the rocks, were we 

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

 millions. 



The \-eeetal)lc kingdom began with the lowest of its kind, the algte or sea 

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

 the deposition f)f the str:ita. It was not until the De^onian age, th:i,t land jjlants 

 appeared of sutticient firmn<'ss for preservation, if we except Dawson's Psi/oji/ii/foii. 

 which probablj' grew in a marsh. These were of the lowest classes. Th■e^• be- 

 cam-e more diffuse and diversified with the lajjse of time ; but the paleozoic era 

 I'losed without the appearance of any of the highei- orders or classes. 



The animal kingdom likewise began with the lowest of its kind, the Enr.aon 

 cii/K/dense. The leai'ned Dr. [laeckel has cstablishctl the fifth sub-kingdom in 

 .'inimal life to include forms below the liiulidtii, and therel'oi'e very nearly related 

 to inorgiinic mattcj-. This sub-kingdom he has called Protistn. The Eor.oon 

 luniiidense, under this clas.sification, Iielongs to the order I'lilijIhuhDnin^ sub-class 

 lliiiliolitn'd^ cl.ass l!lii::iiii<>ij,i, sub-kingdom Prnlisla. Ages passed, aliout which 

 we know very litth', l)cfort> the period of the SI. John's (u-oup, which ushered in 

 the lower Silurian. At this time we find the lowest forms of the Eadiates, .>[ol- 

 lusks and Articulates. The Articulates are representeil liy the lowest forms of 

 theTrilobites, which, in their perfect st:d.e, repicsented the embryonic condition 

 of the existing iu»»7»f.s'. INIillions of ye;\is pass by again, before the ai)pear- 

 ance of rjastcropoda, and Ce|.jhal<.poda, in the I'pper Potsdam Gi'ouii; meantime 

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

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

 higher grade of development. Later still, in the Calciferous Group, the LauielU- 

 briinctiifitfi commenced its existence; a class that has fought its way through all 

 succeeding time, and is even now in the height of its pi'osperity and advancement. 

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

 Lamellibnuichidtd, continued to live, develop, increase their species and o-euera 

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



