272 



IRVING. 



In a description of the rock from the Mato Tepee, Pirrson 

 mentions the occurrence of a mineral similar to that here de- 

 scribed. "There appear also small hexagonal sections of a 

 ainineral which is full of dusty inclusions, and always isotropic. 

 It is supposed to be of the sodalite group, which is also indi- 

 cated by the chlorine shown in the analysis." ^ 



Without a complete chemical analysis of the separate occur- 

 rences and a much closer study of the material than it has been 

 possible to make in the preparatioji of this paper, the writer 

 would hesitate to pronounce this nosean, thus making a separate 

 division of noseanophryes. The rocks in which it occurs have 

 therefore been classed with the phonolites, which they resemble 

 in all other respects. 



Analyses of Phonolites. 





/ 



i 

 // III 



IV \ V \ VI 



VII 



VIII 



IX 



X 



SiO^ 



56.940! 55.62 59.230 



58.560 58.5801 58.940J 



58.980 



59-250 



56.340 



58.65 



A1,0, 



21.031 20.458 21.098 



18.142 ! 17.190 18.III 



16.032 



19.460 



21.057 



16.45 



Fe,03 



J ' 1 1 









r4.o8 



FeO 



I3.408: 4.060 4.132 7.324^ 7.686 6.308 



8.265 



5.076 



4.205 



CaO 



1.930 1. 910 0.640; 1.560: 0.880, 0.570 



I. no 



2.070 



3.340 



3-78 



MgO 



0.327 



0.616 0.472 none ! trace ! 



trace 



trace 



0.709 



trace 



K,0 



4657 



4.3S4 4-486: 5.278 4-536' 6.872' 



4.S98 



3961 



4.082 



4.16 



Na„0 



9.046 



.7.640 



8.670, 8.492 9.261; 7-564 



8.280 



7-391 



9.274 



8.92 



H./:) 



0.390 



0.570 



0. 100 0.120 



0.090 O.09OJ 



0.510 



0.700 



0.070 



0.29 



Loss. 



2.150 



4.220 



1. 180 1. 010 



1.650 



1.360 



2.070 



2.120 



0.900 



2.78 



TotaL 



99.879 



99.478 



100008 100.486 



99-773 



99.815 



100.145 



100.028 



99 977 



99.11 





XI 

 6r.o8 



XII 



XIII 



XIV 



XV 



XVI 



XVII 



XVIII 



XIX 



XX 



SiO., 



55-60 



55940 



57.880 



56.570 



58.090 



58.380 



57- 2 10 



57.450 



58.590 



Al,p., 



18.71 



19 705 



20.905 20.461 



20.736 



2I.28S 



20.395 



1S.673 



20.376 



20.766 



Fe,0, 



1.91 

















FeO 



0.6^ 



5-494 



4-495, 3-770 



5.656 



4.061 



4 423 3.408 



3 630 



4.350 



CaO 



1.58 



1.690 



1.730 0.760 



1.050 



0.810 



1.560 3.070 



1.840 



1.460 



MgO 



0.08 



0.861 



0.421 0.281 



0234 



trace 



trace 



1.099 



trace 



0.464 



K.,0 



463 



4.881 



5.441 5. 112 



4.487 



3-794 



6.261 



4.916 



6.186 



4.803 



Na./) 



8.68 



8 604 



8.866 8,73s 



9- .358 



9-345 



6.234 



6.622 



7.412 



8.170 



H.,0 





0.340 



0.310 0.170 



I. no 



0.200 



0.500 



1. 010 



0.360 



0.090 



I>oss. 



2.21 



2.890 



2.430 2.550 



1.490 



2.260 



2.700 



3.610 



2.760 



0.920 



Total. 





100.065 



100.538199.722 



99.691 



99.848 



100.453 



99.618 



100. or4 



99.613 



1 L. V. Pirrson, Am. Journal of Scioice, May, 1S94, Vol. XL, VII, page 344. 



