M+ T. L. Watson — Kragerite. 



of the new system. It has been found necessary to give 

 special significance to Ti()., in classifying rocks in which so 

 much primary rutile* is found, such as the one forming the 

 subject of this paper, the several types occurring in the 

 Amherst-Nelson counties area in Virginia, and the new type 

 urbainite associated with anorthosite in the Parish of St. 

 Urbain, Quebec, Canada, recently described by Dr. Warren. f 



There are tabulated in Washington's tables only four 

 representatives of the persodic subrang of monzonase. A sub- 

 rang name has not been suggested for these rocks nor does the 

 analysis of either show the peculiarities of composition of the 

 Norway rock. Since the Norway rock (kragerite) is shown to 

 have an intermediate position in the quantitative system and 

 on account of its unusual composition, no name for the mag - 

 matic division is suggested. 



In high titanium and feldspathic content, and in being a dif- 

 ferentiation product of a gabbro magma, the Norway kragerite 

 is perhaps closest allied to the rutile-rich feldspathic syenite:}: 

 (jpiedmontose) of Nelson County, Virginia, but otherwise the 

 rocks bear little resemblance to one another. From' their cal- 

 culated norms, the two rocks fall into different classes in the 

 quantitative system ; the Norway kragerite is a dosalane 

 (class II), the Virginia piedmontose is a persalane (class I). 

 Both rocks are alike in occupying new positions in the quanti- 

 tative system. 



Brooks Museum, 



University of Virginia. 



* Cross, W., Iddings, J. P., Pirsson, L. V., Washington, H. S., Modifica- 

 tions of the Quantitative System of Classification of Igneous Eocks, Jour, of 

 Geol., vol. xx. pp. 550-561. 1912, 



t Warren, Chas. H., this Journal, vol. xxxiii, pp. 263-277, 1912. 



% Watson, Thomas L., and Taber, S., Bull. U. S. Geol. Survey, No. 430, 

 1910, pp. 200-213 ; Bull. Va. Geol. Survey No. 111. (In press.) 



