Wright and Larsen — Quartz as a Geologic Thermometer. 441 



of large pegmatite dike. Massive and clear material. Spec. 

 539. (E. 8. Bastin, collector.) 



16. White quartz. J. A. Fisher feldspar quarry, Topsham, 

 Maine. Large mass of pure quartz several feet across in 

 pegmatite dike. The masses of pure quartz and feldspar at 

 this quarry grade irregularly and without break into coarse 

 to tine graphic intergrowths of these two minerals. Spec. 

 699. (E. S. Bastin, collector.) 



17. White quartz from pegmatite dike one mile northwest of 

 Cumberland Mills, near Portland, Maine. Dike cuts mica 

 schist and granodiorite. Large quartz masses grade into 

 coarse granite pegmatite, either gradually or abruptly. . 

 Large quartz masses appear to form end product of the 

 pegmatite crystallization. Spec. 717. (E. S. Bastin, collector.) 



18. Quartz associated with rounded lepidolite and bladed albite. 

 Berry feldspar quarry, Poland, Maine. This specimen was 

 taken from the gem-bearing portion of the pegmatite dike 

 from which the Spec. No. 15 of smoky quartz was derived. 

 The portion of the dike bearing lepidolite and albite is 

 marked by pockets containing crystal quartz and occasional 

 gem tourmaline, and appears to have been without doubt the 

 last to crystallize out. Spec. 402. (E. S. Bastin, collector.) 



19. Quartz from pocket in very coarse-grained pegmatite. 

 Major Willis feldspar quarry, Topsham, Maine. Spec. 371. 

 (E. S. Bastin, collector.) 



20. Quartz from coarse-grained pegmatite. Old feldspar quarry, 

 Northwest side of Mt. Ararat, Topsham, Maine. Quartz 

 crystal with faces projecting into feldspar. Spec. 361. (E. S. 

 Bastin, collector.) 



21. Quartz from pegmatite in granodiorite two miles east of 

 Dress Pt., Hassler Island, Behm Canal, Alaska. Aplitic 

 pegmatite, coarse-grained and consisting essentially of quartz 

 and oligoclase with some muscovite and biotite. Spec. 5 

 F.W. 50. (Fred. E. Wright, collector.) 



22. Quartz from small granite pegmatite dike. Railway cut 

 opposite Rumford Falls near Rumford Falls, Maine. Typical 

 pegmatite from southern part of Maine. Spec. 440. (E. S. 

 Bastin, collector.) 



23. Quartz from graphic pegmatite. Andrews feldspar quarry, 

 Portland, Conn. Specimen fairly coarse-grained and consist- 

 ing essentially of quartz and feldspar. (E. S. Bastin, collec- 

 tor.) 



24. Quartz from granodiorite pegmatite, West Entrance Point, 

 Bailey Bay, Behm Canal, Alaska. Aplitic pegmatite, coarse 

 grained and similar in composition to No. 19. Spec. 5 F.W. 

 40. (Fred. E. Wright, collector.) 



25. Quartz from graphic pegmatite. J. A. Fisher feldspar 

 quarry, Topsham, Maine. This specimen was taken from 

 the same quarry as No. 16 and is interesting because it appears 

 to have been formed above 575°, while the large masses of 



