154 EVOLUTION AND DOGMA. 



evidence before us, estimate its duration at less than 

 seventy thousand years, during which time we have 

 no evidence of any change in species, but, on the 

 contrary, the strongest proof of the absolute perma- 

 nence of those species whose past history we have 

 been able to trace." 



But strong as is the evidence just adduced, against 

 the mutability of species, that based on the investi- 

 gation of the eminent French paleontologist, Joachim 

 Barrande, is, so we are told, even more conclusive, 

 and that for the reason that it extends over a vastly 

 longer period of time. Barrande was undoubtedly 

 one of the most careful and most successful inquirers 

 into the life-history of certain periods of the remote, 

 geologic past, whom the world has yet known. In 

 Bohemia he had an exceptionally favorable area for 

 the study of the fossiliferous strata of the Silurian 

 Age, and his masterly work, " Systeme Silurien de 

 la Boheme," the most complete production of the 

 kind in existence, will ever remain a noble monu- 

 ment to his untiring industry and his incomparable 

 genius for research in the domain of the earlier forms 

 of terrestrial life. 



The conclusion which this eminent man of science 

 arrives at, after long years of patient investigation, 

 and after the most careful examination of many 

 thousands of specimens, is, to quote his own words, 

 as follows : "Among the three hundred and fifty 

 species (of trilobites) of Bohemia, there is not a sin- 

 gle one which can be considered as having produced 

 by its variations a new specific form, distinct and 

 permanent. Thus, the traces of transformation by 



