1 882.] Geology and Paleontology. 755 



two most ancient portions of the present great system, were once 

 separate rivers, emptying- into a northern extension of the great 

 .gulf; and it is practically certain that neither of them received 

 that portion of the molluscan fauna which now so strongly char- 

 acterizes them, until after the confluence with them of the west- 

 ern portions of the present great river-system which brought that 

 fauna from its ancient home in the western part of the continent." 

 He concludes that " a large number of the types among the Mol- 

 lusca of the Mississippi drainage system have come down wholly 

 unchanged from a time at least as remote as the Laramie period. 



Whitfield's new species of Fossils from Ohio —This pam- 

 phlet contains descriptions of numerous new species of mollusks 

 from the palaeozoic rocks of Ohio, which are to be republished ac- 

 companied by illustrations, in the forthcoming volume of the 

 palaeontology of Ohio. Among the more interesting novelties is 

 a new Eurypterus. 



Davis on the Little Mountains east of the Catskills.— The 

 first number of the third volume of " Appalachia," contains an 

 account of the interesting and varied geology of the Little 

 Mountains, a region attractive to tourists. The illustrations ac- 

 companying the article are clear and excellent of their kind. 



Geological Notes. — At a recent meeting of the London Geo- 

 logical Society, J. S. Gardner communicated a note upon the 

 geology of Madeira. In the center of the island is a horse-shoe 

 shaped valley, more than 2500 feet above the sea, with walls 3000 

 or more feet in height. This the writer regarded as the basal 



wreck of a volcanic mountain. In the June number of the 



Geological Magazine, YV. H. Hudleston continues his contribu- 

 tions to the palaeontology of the Yorkshire oolites ; W. Keep- 

 ing writes upon the glacial geology of Central Wales, and 

 mentions that Aberystwith beach is' rich in agates, onyx, fel- 

 sites, and other stones that cannot have come originally from 

 any part of Wales, but are probably washed by marine cur- 

 rents out of a boulder-clay now submerged in Cardigan bay ; 

 C.Davison contributes an article on the theory of vorticose earth- 

 quake shocks ; and the Rev. A. Irving continues his notes on the 

 classification of the European Permian and Trias. Mr. Davison 

 considers that vorticose and twisting shocks are due to the facts 

 that the earth's crust is not homogeneous and isotropic, that 

 the seismic focus may be of any form and magnitude, and may 

 even consist of detached portions; that the disturbances of differ- 

 ent points of the seismic focus are not necessarily of equal in- 

 tensity, and that the disturbances do not necessarily take place 

 simultaneously throughout the whole extent of the seismic focus. 

 —-At recent meetings of the Geological Society of London, J. 

 W. Hulke, the president, described the pubis and ischium of 

 urnithopsis eucamerotus, a dinosaur allied to Ceteosaurus, Cama- 



