6 SCHALLER 



as new and it is also described by Hofer^ as new, being determined by 

 zonal relations; but it is considered as doubtful by Goldschmidt,^ he 

 suggesting that the correct symbol may be {0.14.14.1 | though San- 

 soni's measurements, like the writers above, agree well for 1 0.13.13.1 1 . 

 Fig. 2 shows one of the smaller crystals of this group with the impor- 

 tant forms developed at one corner. As shown in this figure, the 

 combinations vary at similar crystallographical places, being ofttimes 

 much simpler at some corners than others. While all the intersection 

 lines are here drawn straight, most of them are considerably curved 

 on the crystals, this being particularly true of the larger crystals, 

 which, moreover, show a much simpler combination than the smaller 

 ones. Fig. 3 is an attempt to show the actual appearance of these 

 larger crystals. 



3. CALCITE FROM CALIFORNIA 



The crystals here described were collected by the writer some 

 years ago. They occurred in cavities in what seems to be an altered 

 rock near Fort Point, San Francisco. They were found in the same 

 locality which has furnished pectolite and datolite^ as well as apophyl- 

 lite and gyrolite^ though the crystals here described were not found 

 directly associated with any mineral other than quartz. The crystals 

 are of the common scalenohedral v habit of calcite with e and r as 

 termination, and often reach a size of several cms. They differ some- 

 what from the ordinary calcite crystals, in that the form T { 5382 } 

 is almost always present as a very narrow face below v and minute 

 faces of A/" 1 4.16.20.3 | are also almost always present. One single 

 crystal, colorless and transparent, and about 4 mm. in diameter 

 showed some differences from the other crystals and was therefore 

 measured. The essential difference was that the e faces were replaced 

 by two faces of 3':{2358i, the e faces being entirely absent. In 

 addition a new form in the zone r e was noted. The forms present 

 on this_crystal are: r 1 1011 } , •z;|2131|, r {5382 | , y: | 2358 } , N 

 { 4.16.20.3 } , and the new form fe { 1 .6,7.13 \ . The average measured 

 angles are compared with the calculated one in the following table: 



•Index. Kryst. Form. I, 388. 



* Bull. Dept. Geo!. Univ. Cal., ii, no. 10, 1901. 



» Bull. U. S. Geol. Survey, S6S, 124, 1905. 



