DALE OWEN ON THE WESTERN STATES OF NORTH AMERICA^. 445 



which are below high water of the Ohio river at Cincinnati. The 

 rest occur in the upper beds in the hills about Cincinnati and its 

 vicinity. 



One of the most remarkable fossils found in this formation in 

 Iowa is a multilocular shell four feet in length, now in my collec- 

 tion, supposed to belong to the genus Actiiioceras of Bronn. 



It would exceed the limits of this paper to enumerate all the or- 

 ganic remains which have been found in the blue limestones and 

 marls ; but in addition to those already adverted to, the following 

 must not be omitted, since they may be considered peculiar, and 

 give character to this group: Conotubularia Ciivieri, C. Goldfussi, 

 Troost, C. Brongniarti, Troost ; Bellerophon {acutus ?), B. Nash- 

 villensis, Troost; Maclurites magna^ Lesueur, and another species 

 o^ Maclurites*; Turbo blcarinatus, Troost, Isotelus planus, Cyatho- 

 phyllum ceratites (?) ; a. J^avosites, species undetermined; Lingula 

 JLewisi^ Orthis excentricutn, O, alternata (?), O. alatus, Sowerby. 



There is one circumstance connected with the palaeontology of 

 these rocks that deserves particular note ; it is the occurrence in 

 them of fossils belonging to the genus Asterias. The Asterias an- 

 tiqua was found by Troost in the limestones of Middle Tennessee 

 (members of this group), an account of which was published in the 

 Transactions of the Geological Society of Pennsylvania for 1835, 

 vol. ii. p. 232. 



Besides this individual, Troost found five other species belonging 

 to the same genus, all in rocks below the coal-measures. I have a 

 fossil, somewhat imperfect, which appears to belong to the family, 

 though I am not certain of its exact geological position, for I did 

 not find it in situ. I have little doubt however, from the locality 

 in which it was found, that it belongs to rocks below the coal- 

 measures ; so that it appears that this family existed before the de- 

 position of our coal-measures and during the formation of the oldest 

 rocks of the valley of the Ohio, forming a remarkable exception to 

 observations hitherto made on European rocks, \vhere, I believe, no 

 fossils of the kind have been found in strata older than the Muschel- 

 kalkf. 



These fundamental rocks of the Ohio valley I consider the equi- 

 valents of the Lower Silurian rocks of Murchison, the lower beds, 

 for a thickness of from 75 to 100 feet, corresponding probably with 

 the Llandeilo flags, and the rest with the Caradoc sandstone ; while 

 the corresponding formations of New York appear to be the Trenton 

 limestones and shale, representing the former or older series, and the 

 Salmon river and Pulaski sandstones and shale the latter. • 



The blue fossiliferous limestone is but little metalliferous. The 



"^ I am not certain that this species occurs in the blue limestone ; the genus 

 Maclurites is found also, and more abundantly, in the upj)er beds of the inferior 

 stratified rocks beneath this group, and is considered one of the most ancient 

 shells of our formations, since few, if any, fossils occur beneath the strata con- 

 taining it. The Maclurites is not multilocular. 



t [Since the period when this paper was written, true starfishes of various 

 kinds have been found in palaeozoic rocks even so low down as the Silurian se- 

 ries. — Ed.] 



VOL. II.— PART I. 2 C 



