Cincimiatian and Lexington Fossils 79 



as Trinuclcns conccntricus occurs is the Logana limesLone, at 

 Frankfort, Kentucky. Trinuclcns is not known from the Wihnore 

 and Paris divisions of the Lexington formation, nor from the 

 lower, Greendale division of the Cynthiana formation. At \A"est 

 Covington. Kentucky, Trinucleus conccntricus occurs as low as 20 

 feet below the Triarthrus bccki horizon. At New Richmond, Ohio, 

 it occurs 1 1 feet below this horizon. At Point Pleasant, it occurs 

 II feet below the Triarthrus liorizon, and also 35 feet below this 

 horizon. Mature specimens occur at the Triarthrus bccki horizon, 

 and also in the overlying parts of the Fulton layer, at Point Pleas- 

 ant, Ohio, at Ivor, Kentucky, and elsewhere along the Ohio and 

 lower Licking rivers. From this level, it ranges through the Econ- 

 omy member and as far as the middle of the Southgate member of 

 the Eden formation, in Ohio, Indiana, and northern Kentucky. L 

 it abundant in the Eden west of Falmouth, Kentucky. A few 

 specimens, associated with Lcptacna gibbosa, occur in the lower 

 Eden north of Boyd. A short distance northeast of the railroad 

 station, at Ford, Trinuclcns occurs in an argillaceous limestone, 

 associated with Ccratopsis intermedia. It occurs frequently in the 

 Rogers Gap bed, in the. lower Eden, between Sadieville and Rogers 

 Gap. At Sparta, it is common above the railroad level, in strata 

 associated with Prasopora contigua, Eridotrvpa inutabilis, Erido- 

 trypa hriare^is, Ccratopsis intermedia, Primitia bivcrtex, and other 

 fossils indicating a horizon beneath the typical Eden. It occurs 

 in the lower Eden east of Hatton, west of Lawrenceburg, and at 

 the top of the new branch of the Southern railroad, a short distance 

 beyond the junction a mile and a half southeast of Harrodsburg. 

 While the exact stratigraphy of most of these localities has not been 

 determined as yet, it is known that the vertical range of Trinucleus 

 conccntricus diminishes rapidly southwards, amounting to only a 

 few feet ai: the more southern localities. This may be due in part 

 to a thinning of some of the lower Cincinnatian strata southwards. 

 An article entitled Synopsis of the Trilobitcs of North America 

 was published by Dr. Jacob Green in the Monthly American Journal 

 of Geology and Natural Science, volume i. No. 12, at Philadelphia, 

 in 1832. This number should have appeared in June, and it is so 

 dated, but the publisher having become bankrupt, the editor was 

 forced to publish the last number at his own expense. Since a 

 letter from Blountsville, Tennessee, dated August 3, 1832, is noted 

 on page 565, and travel at that time was slow, it is scarcely likely 



