Tlie Position of the Cincinnati Group. 103 



and three fourths, from the top of the Cincinnati Group to the base of 

 the fossiliferous rocks. As we have here estimated the greatest thick- 

 ness of the Cincinnati Group from Canada at 2,000 feet, the true po- 

 sition will be best understood by estimating the depth below the base 

 of the Cincinnati Group at fifteen miles and a quarter. In other 

 words, if all the formations were fully represented here in their great- 

 est thickness, we would expect to find fossils by digging and boring at 

 Cincinnati all the way down for fifteen and one quarter miles. The 

 fact is, however, that part of the earth has always been dry land, whilst 

 another part has been covered with an ocean. The dry land has al- 

 waA's been worn away, as it is at the present time, by the action 

 of rain and atmospheric causes, whilst the ocean bed has gradually 

 filled up, as the Atlantic ocean fills to-day by sedimentary deposition, 

 so slow it may be that one foot of deposit represents more than one 

 thousand years, but nevertheless a true chronicle of the lapse of time. 

 The maximum thickness, therefore, of each of the several groups of strata 

 belonging to the greater geological formations, is the measure of the lapse 

 of the time that transpired during its deposition on the ocean bed, and 

 when placed together, in their order of time and deposition, these groups 

 constitute the true geological column. And where any group of 

 strata is missing, the column of animal life is likewise connected in 

 some manner by its fossil contents elsewhere. The lapse of time is 

 estimated by the thickness of the rocks, and the internal evidences of 

 the manner of their formation. And it is a general rule that where 

 fossils are abundant, and varieties numerous, the deposition of rocks 

 was extremely slow, and where the fossils are well preserved, scarce 

 and uniform in their appearance, the deposition was much more rapid. 

 The larger part of the rocks, too, have the appearance of having been 

 deposited from mineral matter held by the water in chemical solution, 

 so extremely slow, that a Bryozoan could grow on a shell for many years, 

 within one sixteenth of an inch of the mud, without ever being troubled 

 with its near approach, or finding out in old age that he could reach 

 with his cilia any nearer the bottom than he could in his youth. It 

 has been most clearly proven by paleontological testimony, that there 

 was no break in the continuity of animal life during this immense 

 period of time, and especially it is clearly demonstrated that there was 

 no break during the deposition of the nine miles in thickness of the 

 rocks of the Lower Silurian era, and yet the Trilobites and the Ortho- 

 ceratites were the highest organized and largest developed animals that 

 had an existence. Each succeeding group of rocks contains additional 

 varieties and species, and represents a more numerous and higher 

 development of animal life, ranging from the foraminifera to the 



