Rogers — Mineralogical Notes. 43 



striated parallel to their shorter diagonal, and a narrow unde- 

 termined negative scalenohedron beveling the alternate polar 

 edge of 7. Figure 1 represents a crystal of this type. 



One of the smaller crystals was used for the identification 

 of the forms. It did not give very satisfactory images with 

 the reflection goniometer, but the faces are identified. 



Average. Calculated. 



y/sy 1 8-8-16-3/s, 16-8' 8*3 3 59° 0' 58° 28' 



y/vy VI 8-8-1 6-3^ 88-16-3 5 24° 29' 24° 46' 



The average of lOjneasurements on the hand goniometer gave 

 for ^^(0112)^(1102) 45° 54', the calculated being 45° 3'. 



On another type of crystals 5 to _10 cm long, the forms v 

 (2131), y (3251), / (0221) and # (lO'OlO-l) occur. Ordinarily 

 v is the dominant form as in figure 2, but at times y assumes that 

 role, while on several corroded crystals v is apparently absent. 



Crystals of this type are from Mineral Point and Shulls- 

 burg, Wis., and Dubuque, Iowa. Measurements were made 

 with the contact goniometer. 



Still another type occurs at Miflin, Wis. The_ forms are 

 £■ (8-4-I2-1), v (2131), *(0112), r(1011), # (1(H)-10;1). fl- the 

 dominant form is rather rough, v is smooth, e is striated and r 

 is very much corroded: # is a very narrow form truncating 

 the obtuse polar edges of $• . On account of their large size 

 (2|-5 cm ) measurements were made with the contact goniometer 

 with these results : 



#: 



* ®; J (8 4-12-1) 



fl: 



a ^i v (8-4-12-1) 



£: 



zv ®\ V1 (8-4-12-1) 



V 



a v l (2131) 



V 



a v y (2131) 





Av. 



Calc. 



^ (8-124-1) 5 



80° 52' 



81° 20' 



^ (12-4-8-1) 4 



38° 18' 



38° 2' 



^ (4-8-12-1) 6 



24° 45' 



24° 21' 



A (2311 3 



75° 30' 



75° 22' 



a (3121) 3 



35° 40' 



35° 30' 



lew form from 



Colorado. — 



■Some calcite 



crystals from Seguache Co., Colorado, obtained from Geo. L. 

 English & Co., are different in habit from any described jfrom 

 this country (figure 3). The forms observed are */c:, (49'41'90-8), 

 U : (24-8-32-7), r (1011), m (4041), e (0112), c (0001)^ «:, new 

 for calcite, is the dominant form. The faces are bright and 

 give excellent images except e and c, which are striated or 

 roughened. These were identified by their position, the for- 

 mer truncating the polar edge of r. The following measure- 

 ments made with the reflection goniometer identify the forms. 









Limits. 



Average. 



Calc. 



k: ^ 



k: 1 



(49-4l-908)^ (49 90-41 -)8) 7 



65° 28-65° 30' 



65° 29' 



65° 29' 



fC /s 



& v 



(49-41-90-8) ^(90-41-49')8) 6 



53° 48-53° 49' 



53° 49' 



53° 48$' 



Ui * 



M 



(24-8 '32-7)^(4041) 3 



13° 30-13° 31' 



13° 30f 



13° 29' 



u: ^ 



IV. 



1 (24 8 -32 -7) a (24-32-8-7) 3 



88° 48-88° 49' 



88° 48|-' 



88° 48^' 



r 



M 



(1011) ^(4041) 3 



31° 9-31° 11' 



31° 10' 



31° lOf 



