﻿6 NORWOOD AND PRATTEN ON PRODUCTI. 



In the Devonian limestones we have met with only two species, both of which are 

 also found in Europe. One of them, the P. Murchisonianus, it is certain, also belongs 

 to the upper Silurian rocks of Indiana. Several of the species described were found 

 by Mr. Pratten in the Western part of Missouri, and on the Nemahaw river, in Ne- 

 braska, in a limestone, the age of which has not been yet determined. 



In the " Eeport on the Geology of Wisconsin, Iowa, and Minnesota," Dr. D. D. 

 Owen mentions having found the P. marginalis. As we have not met with that 

 species, it is not included in the present catalogue. He also indicates several new 

 species from North-western localities, of which it is to be hoped he will before long 

 publish descriptions. 



At the time M. de Koninck's work was published, the whole number of species 

 known was sixty-two. Dr. D. D. Owen added one from the U. S. Survey. We have 

 now added twelve, which makes the number of the species known, in all countries, up 

 to the present time, seventy-five. It may also be seen, by consulting M. de Koninck's 

 work, that, at the time of publication (1847), the whole number of species known to 

 occur in the United States and Territories amounted only to seven. They now num- 

 ber thirty, and the probability is, that future investigations will greatly extend the 

 catalogue. 



For the beautiful and accurate drawings of the species now published, we are 

 entirely indebted to Mr. H. A. UlfFers, of the Illinois State Survey. 



MOLLUSCA BRACHIOPODA. 



Genus Productus, Sowerby. 

 /Section I. 



PRODUCTI STRIATI. 



P. margaeitaceus, Phillips. — De Koninck, — " Monograph on the Genus Productus." 

 PI. IV., fig. 3. 



Locality. — Twelve miles N. W. of Richmond, Missouri, in calcareous clay, over- 

 lying thick beds of limestone. 



P. flexistria, McCoy. —Qq Koninck's monograph. PI. XVII., fig. 1. 

 Localities and Geological Position. — Found in the mountain limestone of Chester, 

 Kaskaskia and Mountain Bluff, Illinois, and near Stephensport, Kentucky. 



P. cora, A. d'Orbigny.— De Koninck, " On the Fossils of Belgium." PI. IV., fig. 

 4, and PL V., fig. 2. 



Localities and Geological Position. — In the mountain limestone of Chester, Rosiclare, 

 Warsaw, and other places in Illinois ; near Richmond, Missouri ; and at Carrsville, 



