ABSTRACTS OF PAPERS 99 



A HIGH TEMPERATURE VEIX IX MADISOX COUXTY, MISSOURI 



BY W. A. TARR 



(Abstract) 



" A quartz vein cutting granite occurs in western Madison County, Missouri. 

 The vein contains wolframite, fluorite, and zinnwaldite, indicating its forma- 

 tion at higli temperature ; and also pj-rite, sphalerite, galena, chalcopyrite. 

 and arsenopyrite. Serpentine also o'ccurs in the vein and offers an interesting 

 problem as to its origin. 



Read by title. 



CRETACEOUS AGE AND EARLY EOCEXE UPLIFT OF A PENEPLAIN IN THE 

 SOUTHERN INTERIOR OF BRITISH COLUMBIA AND THE DEVELOP- 

 MENT OF THE NORTH THOMPSON RIVER TRENCH 



BY W. L. UGi:ow 



Eead by title in absence of author. 



STUDY OF THE IGNEOUS ROCKS OF ITHACA, NEW YORK. AND VICINITY 



BY J. H. C. MARTENS ^ 



(Abstract) 



The dikes of basic igneous rocks in the Ithaca region occur in vertical north- 

 south fissures which parallel the Jointing of the Upper Devonian sediments — 

 shales, sandstones, and limestones. They will be called dikes, whether the 

 filling was originally entirely of magmatic origin or, as in some cases, largely 

 composed of sedimentary fragments cemented hj a matrix of igneous rock. 

 Metamorphism of the sediments is very slight. 



The rock of these dikes is termed Kimberlite on account of the remarkable 

 similarity of the fresher occurrences with the South African material. Both 

 the micaceous and the mica-poor varieties noted in South Africa are repre- 

 sented here. There are also intermediate facies. Striking similarities in 

 minor mineralogical detail, such as anomalous pleochroism in mica, presence 

 of garnet, etcetera, have also been noted. A chemical analysis of material 

 from one of the more micaceous dikes shows close analogy with the mica 

 peridotite of Crittenden County, Kentuckj^ the alnoite of Mannheim, New 

 York, and some of the South African micaceous Kimberlites. 



The significance of such peridotite dikes, occurring at many widely separated 

 localities in the little-folded paleozoic rocks west of the Appalachians, is dis- 

 cussed. 



The following papers were read in joint session with the Society of 

 Economic Geologists : 



1 Introduced by A. C. Gill. 



