I. Bowman — A Buried Wall at Guzco. 509 



excavation. Trenches dug in well-selected places should yield 

 other walls with even more certain relations. The considera- 

 tions presented in this paper are hased upon a very small col- 

 lection of facts gathered as by-products rather than as main 

 results during a few days field work about Cuzco. If they 

 should stimulate further work in this almost unexplored and 

 certainly very rich field, the object of the paper will be accom- 

 plished. Certainly the temporary conclusions have a most 

 serious bearing on an old problem whose solution should not 

 be postponed much longer, now that a railroad makes access to 

 these ancient treasuries moderately easy. 



Akt. XLIV. — Kragerite, a Butile-oearing Rock from Kra- 

 geroe, Norway ; by Thomas L. Watson. 



Introduction. 



During investigations, which have extended over a period 

 of several years, of the rutile deposits of Virginia for the State 

 Geological Survey, Frank L. Hess of the IT. S. Geological 

 Survey generously placed at my disposal for comparative 

 study several small specimens of the rutile-bearing rock from 

 Krageroe, Norway. Microscopic and chemical study of the 

 rock prove it to be of unusual composition, hence a brief 

 description of the rock with special reference to its relations in 

 the quantitative system is considered appropriate at this time. 



The results set forth in this paper are based entirely on the 

 specimens furnished the writer by Mr. Hess, and they may or 

 may not be wholly representative of the rock mass. The 

 writer has no personal knowledge of the rock occurrence or of 

 its field relations, but a communication from Professor J. H. 

 L. Vogt of Christiania states that the rock (kragerite) has been 

 examined by Professor Brogger, but has not been described in 

 detail. He further remarks that the rock has been found in 

 the neighborhood of Krageroe, but only at a single place, and 

 it has not great areal extent. It has been worked in later years 

 for rutile, the percentage of which is very variable. 



In 1904 Professor Brogger briefly described the rock as a 

 new member of the aplite series and named it kragerite. 

 Through the kindness of Professor Vogt, I give a translation 

 of the short "Besprechung" by Professor Brogger : 



"Brogger discussed a new rock, kragerite, a new member of 

 the aplite series. The rock is of practical interest on account 



