172 PROCEEDINGS OF THE ACADEMY OF 



characters that give the posterior half of the valves much the appearance of 

 some types of Trigonia. 



Locality and position. — Found by Mr. Green, of the Illinois Survey, in Warren 

 County, Illinois, in a black bituminous limestone near the base of the Coal- 

 measure, associated with Lima retifera, and Cardiomorpha Missouriensis. Shu- 

 mard, Aviculopecten ? carbonarius, Stevens, sp., [=Peclen Broadheadii, Svrallow, 

 = P. Hawni, Gein.), Spiriferina Kcntucfcensis, Shumard, Vhonetiis mesoloba, 

 N. & P., Schizodus curtus, M. & W., and various other species, many of which 

 have been generally, until recently, supposed to be mainly confined to the 

 upper part of the Coal-measures.* Mr. Broadhead also found it associated 

 with many of the same fossils near the upper part of the Coal-measures in 

 Fayette countv, Illinois. 



August od. 

 The President, Dr. Hays, in the Chair. 

 Twelve members present. 



August lOfJi. 

 The President, Dr. Hays, in the Chair. 

 Eighteen members present. 



August 17 tJi, 

 The President, Dr. Hays, in the Chair. 

 Sixteen members present. 



On motion, it was resolved, that the Academy take part in the 

 Centennial Anniversary of Humboldt's Birthday, to be held on the 

 13th and 14th of September. Dr. H. C. Wood, Jr., was appointed 

 by the Academy as orator, to deliver an address on the occasion. 



The following paper was offered for publication : " On Brevoor- 

 tia," by Alphonzo Wood. 



August Slsf. 

 Dr. Mayburry, in the Chair. 

 Eighteen members present. 



* 1 have also been interested to see amongst the Illinois State Collections from the 

 shale associated with the coal-bed at Danville, in that State, a new type of bivalves 

 I had never before seen from any other locality tlian Nebra.ska City, Nebraska, where it 

 occurs in the Upper Coal-measure beds referred by Prof. Marcou to the horizon of the 

 Permian. It is a small, smooth, compressed, elongated, equivalve bivalve, with nearly 

 parallel, straight upper and lower margins, and a distinct, rather large rectangular 

 notch in the anterior ventral margin, forrning a hiatus similar to that seen in the . 

 genus A'ylojihar/a, though it evidently has no relations to that group, but seems to be 

 allied to the Snlmidie. In Dr. Hayden's report on the Geology of Nebraska, I have propo.sed 

 for this genus the name Prntlv/ris. 



From the same bed at Danville, HI., I have likewise seen in the State Collection, speci- 

 mens of Prof. Geinitz's Nebraska species GcrvilUa longa, one of which shows the hinge 

 to have none of the characters of Gervillia or Bithevellia, since it has no trace of the row 

 of cartilage pits characterizing those genera. On the contrary, it seems to agree well 

 iu its hinge characters with the genua Avicula. 



F. B. Meek. 



[August, 



