swingle: new citrous genus, pamburus 335 



and presumably governed the formation of the waluewite, the 

 small excess of silica and all of the alumina entering into the 

 waluewite which formed somewhat prior to the monticellite. 



Monticellite occurred in large masses, while the waluewite was 

 quite subordinate in amount. The composition of waluewite 

 suggests a mineral mixture of monticellite + olivine + spinal + 

 diaspore in the respective approximate ratio of 6 : 1 : 5 : 6. 



The recrystallization of the limestone produced a pure blue 

 calcite with coarse rhombohedral texture. Cleavage rhombo- 

 hedrons several centimeters in diameter can be broken from the 

 mass. 



The source of the magnesia, alumina and silica is somewhat 

 problematical. The original limestone was not especially dolo- 

 mitic or argillaceous as the main limestone capping averages 

 about 2 per cent magnesia and about the same in insolubles. 

 The blue calcite with its monticellite, waluewite, vesuvianite, 

 diopside, wilkeite, etc., is very localized in its development, 

 occurring in patches and bands or zones. It suggests an occur- 

 rence near the contact with former dikes or apophyses of igneous 

 rock, and it appears highly probable that the assimilation of the 

 magnesian-felspathic constituents of these intrusions with the 

 lime carbonate by the action of hot magmatic solutions had 

 produced these localized occurrences of hydrometamorphic 

 minerals. 



BOTANY. — Pamburus, a new genus related to Citrus, from India. 

 Walter T. Swingle, Bureau of Plant Industry. 



In 1833 Dr. Robert Wight described as a new species Limonia 

 missionis, a small, spiny tree from the sandy coastal regions of 

 southern India. In 1861 this species was referred to the genus 

 Atalantia by Oliver, who notes, however, that it is " rather iso- 

 lated in its general fades as well as by precise characters." 1 

 Subsequent botanical writers have followed Oliver in referring 

 this plant to Atalantia. 



1 Oliver, D. Nat. order Aurantiaceae. Journ. Linn. Soc. 5 (suppl. 2) : 12. 

 1861. 



