No. 4. J BILLINGS — ON THE TACONIC CONTROVERSY. 461 



to the otiier side of the Atlantic. I therefore thought myself right 

 in effacing- the American name, and in substituting that of P. spinosus. 

 A short time afterwards I experienced the same illusion at the School 

 of Mines in Paris. You may perceive by this how evident it is that 

 these two forms are identical. 



" After this fact, I think with you, that the opinions of our Ameri- 

 can confreres might well be modified. Besides you are aware that 

 my doctrine, often expressed, is that the local deposits of countries, 

 distant from each other, do not necessarily correspond exactly, one to 

 one. * * * 



" Nothing is more remarkable than the apparition of the three 

 Olenus of Vermont, described by J. Hall in the pamphlet which 1 owe 

 to your kindness. I demand of you, before all, if the figures are of 

 the natural size, because there is nothing said about it in the text. 

 The dimensions figured, greatly exceed those of the congeneric species 

 of the ancient continent. You have good reason certainly to consider 

 the apparition of these three species, in the Hudson River group, as a 

 fact analogcfus to that of my colonies, * * * 



'« These three Olenus reproduce certainly the forms, which appear 

 in Europe, only in the Primordial fauna. Consequently they would 

 constitute by themselves, the phenomena, of the re-apparition of a 

 genus heretofore considered as having become extinct with the prim- 

 ordial fauna. It would be a fact analogous to the Colonies, and I 

 would be happy to be able to cite it in the work w^hich I am prepar- 

 ing upon that subject, and which I hope to publish soon. But before 

 placing that fact among those on which 1 found my doctrine, you will 

 perceive that it is indispensable for me to obtain a perfect security of 

 its reality. * * * 



" You will render me a great service, if you can send me the facts 

 which I have asked you for. If the three Olenus of Greorgia represent 

 really a re-apparition of an extinct type, or a sort of a colony, that 

 fact would be very apropos for me, since it will show that on the new- 

 continent the succession of organic beings has been subjected to 

 anomalies, similar to those which I have discovered in our old 

 Europe. But if by chance, by some local accident, hitherto not per- 

 ceived, there has been an illusion, very conceivable, as to the age of 

 the Georgia slates holding the Olenus, it would simply be in America 

 a repetition of that which has taken place in England, in Spain, and 

 in Germany, as I have already related to you. * * » 



J. Barrande." 



The above is quite sufficient to prove, that I had recognized 

 the trilobites to be primordial, before tlie pamphlet in which they 

 were figured was sent to Barrande. Prof. Hall had referred 

 them to Olenus, but I have been assured by several of the geolo- 

 gists who followed him, that he never intimated to them that the 

 fossils indicated a horizon lower than that of the Hudson River 



