1 882.] Mineralogy. 607 



lines of gill-bearing fresh-water mollusca, now separated from 

 each other by barriers of land and sea that they are incapable of 

 passing, by showing that the rivers in which kindred forms occur, 

 once formed part of the drainage of inland lakes that have since 

 become obliterated, and thus there was formerly a continuity 



which is now destroyed. Chas. U. Shepherd follows with a 



notice of Monetite and Monite, two new minerals obtained from 

 the twin islands Mona and Moneta, near Porto Rico, W. I. 

 Both are phosphate of lime, formed in the caverns of limestone 

 rock by the infiltration of the soluble ingredients of the bird- 

 guano upon the surface. Dr. Lemoine has communicated to 



the French Academy the result of his late palaeontological re- 

 searches upon the mammals of the Eocene beds around Rheims. 

 The study of cerebral casts of Arotocyou and PlLuraspiaothcriun.. 

 show relations to the embryonal brains of living mammals, and to 

 those of certain marsupials, since the cerebral hemispheres leave 

 the quadrigeminal tubercles completely uncovered. The den- 

 tary formula of PUuraspidotherium and Plesiadapis recalls that of 

 certain Australian phalangids. M. Lemoine has formed the genus 

 Adapisorex to include some very small mammals, equally re- 

 lated to the Phalangids, found by him in the environs of Rheims. 



The Proceedings of Acad. Nat. Sci. Phil., contain Part 11. 



of a revision of the Palaeocrinoidea, by Chas. Wachsmuth and F. 

 Springer. This extensive paper occupies 238 pages, and is illus- 

 trated by three plates. It is devoted to the families, Platycrinidae, 

 Rhodocrinidae, and Actinocrinidre. Two species of Jiato'crinus, 

 and three of Eretmocrimis, all from the Burlington and Keokuk 

 limestones of Indiana and Iowa, are described. In the same 

 Proceedings, Angelo Heilprin has a " Revision of the Cis- 

 Mississippi Tertiary Pectens of the United States ; " " Remarks 

 on the Moll usenn genera llippagits, Vcrticordia, and Pecchiola;" 

 a " Note on the Approximate Position of the Eocene Deposits of 

 Maryland," in which those deposits are referred to a horizon 

 nearly equal to that of the Thanet sands and London clay of 

 England and the Braccheux sands of the Paris basin, that is, near 

 the base of the Eocene series ; ami a " Revision of the Tertiary 

 species of Area." 



Proceeding 



of the Proceedings of the Mineralogical and Geological Se 

 of the Academy of Natural Sciences has just been publi 

 The first number was published in iSSo. and contained the 

 ceedmgs from 1877 to 1879, inclusive, consisting ot fiff 

 articles, a number of which 'have been noticed in foreign pt 



