On date of Report on Geology of Wisconsin, 157 



words, "Published Nov., 1861." I do not recognize the hand- 

 writing, but it is evident that one of the dates must be incorrect, 

 and I believe both are. I have some evidence that the report was 

 not published until about the middle of December, 1861, eleven 

 months after the date printed on the cover, and I am obliged to 

 call attention to it for the following reasons : 



On the 21st of November last, I pubhshed a paper containing 

 descriptions of a number of new species of fossils, principally from 

 the Potsdam sandstone and other associated formations. On the 

 22nd I sent a copy to I'rof. Hall by mail. In the January No. 

 of SilHman's Journal, he alludes to it in his letter on the Pots- 

 dam sandstone, and Hudson River rocks of Vermont. As a gen- 

 eral rule, articles intended for that Journal must be in the hands 

 of the pubHshers about one month previously to the date of pub- 

 lication. It seems quite certain, therefore, that my paper was in 

 Prof. Hall's possession in the latter part of November, most pro- 

 bably about the 24th of the month. In my paper I described a 

 new genus of fossil Brachiopoda under the name of Obolella, 

 One of the species to which I referred as exhibiting the characters 

 of the genus, occurs in the Potsdam sandstone of Wisconsin, 

 Prof. Hall has described this species on p. 24 of his report, under 

 the name of Lingula polita, and has also pointed out that its 

 characters are not the same as those of either Obelus or Lin- 

 gula. His remarks are in substance the same as mine except 

 that he notices an " obtuse dental process on each side of the 

 rostral cavity," which is not visible in any of our specimens. On 

 comparing the two papers any person would be justified in sup- 

 posing that I had taken the idea of the genus Obolella from Prof. 

 Hall. Thus by antedating his report eleven months, he lays me 

 open to the charge of plagiarism, which is certainly very unfair. 

 I never saw his report, nor had any knowledge of its con- 

 tents, nor of its existence, until I saw the notice of it in this 

 Journal in the beginning of February, 1862, at which time the 

 December number was issued, — more than two months after my 

 paper was distributed, and fourteen months after the time he has 

 given the public to understand that his was published. I am com- 

 pelled, therefore, in self-defence, to correct his erroneous date. 



Some of my scientific friends have advised me to take no notice 

 of this and similar matters. They, however, are engaged in dif- 

 ferent fields of research from that occupied by Prof. Hall and 

 myself, and as they cannot come into collision with him, thev can 



