CONTRIBUTIONS TO PALEONTOLOGY- 131 



GENU'S OBOLELLA (Billings, 1861), 



'^Generic characters. Shell ovate, circular or subquadrate, convex 

 ^* or plano-convex. Ventral valve with a false area which is 

 ■" sometimes minute, and usually grooved for the passage of the 

 ^' peduncle. Dorsal valve either with or without an area, Mus- 

 ^' cular impressions in the ventral valve four:; one pair in front 

 ■*' of the beak near the middle or in the upper half of the shell, 

 ^' and the others situated one on each side near the cardinal 

 ** edge. Shell calcareous. Surface concentrically striated, some- 

 *'■ times with thin extended iamellose ridges, 



"In general form, these shells somewhat resemble Obolus, but 

 *' the arrangement of the muscular impressions is different. In 

 *^ Obolus, the two central scars have their smaller extremities 

 *^ directed downwards and converging towards each other; but 

 "" in this genus, the arrangement is exactly the reverse,''* 



* In my Annual Eeport on the Progress of the Geological Survey of Wisconsin for 

 1860, I described as Lingula? polita* a fossil possessing characters intermediate to 

 LiNGULA and Obolus. I remarked that the shell had been referred to Obolus by Dr. 

 D. D. Owes, but that I was then unable to find satisfactory evidence of the characters 

 of Obolus : neither were tlie characters those of true Lingula. This Report was in 

 the hands of the authorities, and the first form printed during my stay in Madison 

 between the 25th of February and the 5th of March 1801^ but the printing of the work 

 ■was not resumed till the November following. t 



Some time before the middle of December 1801, I received the pamphlet of Mr, 

 BiLLiiVGS, published the 21st November, containing the description of the Genus 

 Obolklla.^ In this pamphlet he cites as one of the genus '' a small species from the 

 *■' Potsdam sandstone of the St. Croix river in the Western States, where it occurs 

 "*' associated with primordial Trilobites described by the late eminent geologist Dalk 

 •*' Owen." 



Subsequently my attention was very rudely called to this paper by an article in the 

 Canadian Naturalist by Mr. Billings, charging me with having availed myself of the 

 knowledge given in his pamplet relative to Obolella, to make the comparisons cited 

 above. The same article, or a similar one, was republislied in the American Journal of 

 Science, wliich has shown a remarkable avidity in publishing anything that might cast 

 reproach upon m.y labors, or injure me personally. 



The fact that the shell which I had under consideration had been referred by Dr. 

 Owen to " Odolus, Obolus apollinu^, and Obolus ( ApollinusI)"J, was certainly 



* In printing of this Report, beyond the first form, bo proofs were submitted to me, and the 

 quere after Lingula (?) was omitted by the printer. 



t For evidence regarding the date of printing this Report, see Journal of the "Wisconsin 

 Senate, " Fifteenth Annual Session", pa^e 181. 



I Sec Geological Report on Wisconsin, Iowa and Minnesota, pp. 50, 53, 501, etc., and Tablo 

 of species, etc. 631 ; also Explanation of Tab. 1 B. 



