248 PROCEEDINGS OP THE AMERICAN ACADEMY 



first observations he recognized a different system from that of the 

 groups of Wenlock and Ludlow, and that in calling it '• Cambrian " he 

 followed the rules recognized in stratigraphy for establishing the great 

 formations or systems. 



But we must go back, to show the progress accomplished, first out- 

 side of England, and then in England itself. 



The publication of " The Silurian System," in 1839, was truly an 

 event, and marks an important point in the progress of geology. 

 Nevertheless, it is well to say that this book had at first hardly any 

 influence in America, and only after the visit of de Verneuil, in 1846, 

 did it attain a certain limited influence. 



Since 1836, Vannuxem, P^mmons, and Conrad had studied with the 

 greatest success the " Transition formations " of the State of New 

 York. The beds being in part horizontal, or nearly so, and succeed- 

 ing each other in a receding series, the American geologists easily 

 established a good classification without having to make the difficult 

 connection and joining which arrested Murchisou and Sedgwick in 

 England. 



In Europe the publication of the *' Silurian System" had at once a 

 very great influence, owing to very diflferent causes. In the first place, 

 the author went over Europe in all directions, trying everywhere to 

 recognize and establish his Silurian classification. 



There was a sufficient resistance by the German, Scandinavian, and 

 Russian geologists ; but he succeeded in surmounting it, thanks to the 

 French geologists, always much disposed to Anglomania. Barrande 

 it was, above all others, who made the fortune of the " Silurian Sj's- 

 tem." Exiled at Prague with the royal family of France, Barrande 

 had already for some years been studying the basin of Bohemia, 

 systematically collecting both fossils and geological sections. The 

 want of points of comparison, and the resistance of the Boliemian 

 geologists and paleontologists, who declared that the geology of that 

 country was unique, and unconnected with anything similar in llie 

 earth's history, caused Barrande to receive the first copy of the 

 " Silurian System," at Vienna, in 1840, with the same joy that a sailor 

 by night in a fog perceives a lighthouse. And in gratitude for the 

 great service this book rendered him, he not only employed the terra 

 '■ Silurian," but extended it to strata far below the level of those 

 described by Murchison, adding at once an average of ten thousand 

 two hundred feet of beds containing the primordial faiuia, his division 

 C, — entirely unknown to Murchison and Sedgwick, — and also his 

 azoic beds A and B. 



