XXIV THE PALEONTOLOGY OF MINNESOTA. 
Those from the Hudson River group are:— 
Plants. 
Buthotrephis subnodosa. 
Corals. 
Cheetetes lycoperdon. —? nov. genus and sp. 
Favistella stellata. Catenipora gracilis, n. sp. 
Streptelasma — n. sp. Syringopora obsoleta, n. sp. 
Crinoidea. 
Columns of Heterocrinus and Glyptocrinus. 
Brachiopoda. 
Lingula quadrata. Orthis subquadrata. 
Orthis testudinaria Leptzna alternata. 
O. occidentalis L. sericea. 
O. subjugata. Atrypa increbescens. 
Acephala. 
Ambonychia carinata. Modiolopsis anadontoides. 
Avicula demissa. Nucula — ? 
Modiolopsis modiolaris. Lyrodesma — ? 
M. pholadiformis, n. sp. Cleidophorus planulatus. 
Gasteropoda, 
Murchisonia gracilis. Bellerophon bilobatus. 
Cyrtolites ornatus.. 
Cephalopoda. 
Orthoceras lamellosum. Ormoceras crebriseptum. 
Crustacea. 
Tsotelus megistos. 
In the classification of the formations (pp. 2-7) Messrs. Foster and Whitney distinctly 
separate the Galena limestone from the ‘‘Cliff or Upper Magnesian limestone,” of which it 
had hitherto erroneously been supposed to be a part. But the interlying Blue shale (the 
Maquoketa) they suppose to be ‘‘associated with No. 3, or the Blue limestone and marls of 
the west,” which at that time were regarded, without dissent, as the equivalent of the 
Trenton. It is plain therefore that although they distinctly recognized the Hudson River 
strata in Green bay, overlying the Galena beds, they could not satisfactorily adjust the 
“Blue shale” of Locke in the Mississippi valley, in the same position. The term Galena 
limestone is first met with in this report. 
This separation was evidently due to the paleontological determinations of Prof. 
James Hall, who in Chapter 1x details the geographic distribution of the Chazy, Birds- 
eye and Black River formations, and names the fossils found by him in the lead-bearing 
rock, none of which could be assigned to the Upper Silurian. He remarks that if the 
Hudson River beds of the Green Bay region should finally be discovered in the Mississippi 
valley they must lie above the Galena limestone, but that he had been unable to trace them 
from one region to the other. 
D. D. Owen. 
1852. Report of a geological survey of Wisconsin, lowa and Minnesota; and incident- 
ally of a portion of Nebraska territory, made under instructions from the United States 
treasury department, by David DALE OWEN, United States geologist, Philadelphia, 1852, 
4to, numerous illustrations, maps and plates, pp. XXXVI and 635. 
