Zeolites of Minnesota. — Winchell. ijj 
Localities. It Has been noted at the following points, but 
occurs in many others: east of Pork bay. in veins; at north- 
east corner section 28, 59-4W; two miles west of Little Marais. 
Laumontite . This is the most abundant of the zeolites 
of Minnesota. It is found not only in nearly every scoriace- 
ous trap-flow from Lester river eastward as far as to Grand 
Portage bay, but is abundant also in the soft red conglomer- 
ates which consist very largely of the debris of the basic erup- 
tives. It occurs in small nests, filling cavities sometimes two 
inches in diameter, and in amygdaloidalvesicules. Its fibers 
radiate from points and are of a red or flesh red color but 
nearly white when fresh, but easily crumble away and dis- 
appear. They have extinction at 25°-30° frcrm parallelism. 
The acute bisectrix is //p but does not appear in cleavage sur- 
faces. These present //m, the easy cleavage being parallel to 
010 which contains the optic plane. The elongation of the 
fibers is usually positive. 
Localities. Some of the most important localities are: 
southeast Va, section 34, township 51-13, east of Lester river 
in an amygdaloidal diabase, where may be seen an unusual dis- 
turbance of the strata, dipping in opposite directions, consist- 
ing of an acid scoria; mouth of Knife river and eastward to 
Agate bay; Little Marais, six miles east of Temperance river; 
three miles east of the mouth of Poplar river; at the beach east 
of Grand Marais. Laumontite is usually accompanied bv cal- 
cite. 
Mesotype. This mineral has been found in Minnesota in 
but one locality. With positive elongation and quadrangular 
sections, the axis 11^ perpendicular to the base, the axial plawc 
stands so as to subdivide the angle between the faces no and 
no. By micro-chemical test this mineral gave evidence of 
containing only soda. 
Localities. Beaver Bay in veins in the gabbro (anor- 
thosyte) masses at the west side of the bay. 
