have an extended, and many a cosmopolitan range. Thus Potamogeton perfoliatus Linné extends over more than twenty degrees of latitude in North America and is found also in Europe and Asia.

All of the wide ranging forms extend into both high and low latitudes whereas species of restricted range are commonly confined to warm regions. Climate is less of a factor in aquatic than in terrestrial vegetation, but in spite of this it would appear that the glaciation of the Pleistocene in the lands of the Northern Hemisphere was one of the factors in extending the range of the present wide ranging forms, and that these are geologically older than those species of restricted range.

ART. XXIX.-Additional Notes on the Crystallography and Composition of Boulangerite; by EARL V. SHANNON.1

Existing knowledge of the crystal form of boulangerite rests almost entirely upon the work of Sjögren' upon material from Sala, Sweden, which showed the composition of this mineral to be different from the formula usually given and endeavored to show its relation, both chemical and crystallographic, to diaphorite. The present writer has recently published a paper on the chemical composition of this mineral with 8 new analyses made upon material from various localities which apparently confirm Sjögren's conclusions relative to its composition." Additional study of one of the specimens analyzed has shown the presence of measurable crystals which have been made the subject of the following notes. The exact history of the specimen is somewhat uncertain but it is known to be from the Wood River district in Blaine County, Idaho and it is probably from the Independence mine. An analysis of the material is given in the publication above cited. The crystals occur as small rosettes

Published by permission of the Secretary of the Smithsonian Institution. Geol. Fören. Förhandl., 19, 153-67, 1897.

Proc. U. S. Nat. Mus., 58, 589-598, 1920.

associated with pyrite and drusy quartz along a rift in a mass of white vein quartz containing disseminated pyrite crystals and fibrous masses of boulangerite. They reach a maximum length of about 1 millimeter, and are highly polished with metallic luster and light lead-gray color. They are all tabular parallel to the front pinacoid a (100) and seem to possess a distinct cleavage parallel to this plane. Several of the crystals were detached from the matrix and measured with a Goldschmidt 2-circle goniometer.

The crystals are all similar in habit, the dominant forms being the macropinacoid a (100), the prism n (120) and the pyramid (124) while several other prismatic forms occur as narrow faces, the form and habit of the crystals being illustrated in fig. 1. The prism zone is strongly striated vertically.

The angles measured were found not to be in entire agreement with those given for the same forms by Sjögren and a question arose as to the advisability of substituting new axial values for this mineral. To this end the description of the mineral from the Swedish occurrence was carefully considered. The crystals from Sala, which seem to have been very minute, were obtained by dissolving the carbonate gangue with dilute hydrochloric acid. Although Sjögren states that the forms in the prism zone gave quite good angles, the crystals are said to have been strongly striated vertically and it seems probable that the quality of this zone on the present writer's crystals was fully as good as that on the crystal examined by Sjögren. He states clearly that the measurements recorded in his table were made on one and the same crystal on which the only terminal face was found, the dome u (012), upon which he bases his value for the c axis. This yielded only one measurement which was so poor as to be scarce usable at all. Five crystals from the Idaho occurrence were measured and on each of these the prism n(120) and the pyramid (124) were present as distinct faces yielding good signals although the angles measured varied somewhat. By weighting each angular measurement according to quality the following average is obtained for the form (120):

n (120)

while the pyramid (124) gives the following average angles:

Since the latter form yielded the better reflections its angles were taken as fundamental for calculating the crystallographic constants yielding the following:

a = .5038 log a = 9.70226 log p.

10.13386 p.

= 1.3620

c = .6862 log c = 9.83645 log q。 = 9.83645 q = .6862 The axial ratios thus derived may be compared with those given for boulangerite by Sjögren and those of diaphorite as follows:

Boulangerite (new)

Boulangerite (Sjögren)
Diaphorite.

с

a : b :
.5038 : 1 : .6862

.5527 : 1 : .7478
.4919 1.7345

:

The crystals from Idaho show a well-defined cleavage parallel to a(100) while Sjögren does not mention any such cleavage in the material from Sala nor is such a pinacoidal cleavage given for diaphorite. The forms observed on the crystals from Idaho are given with their calculated and measured angles in the following table:

Forms and angles of boulangerite from Idaho.

Sjögren sought to show that boulangerite was the lead extreme of a series having the general composition expressed by the formula 5(Pb, Ag2) S.2SbS, which is the formula which has been accepted for some years for diaphorite. In a recent paper Wherry and Foshag1 have recognized the fact that lead and silver are not isomorphous in minerals of this type but that, when these bases of unlike valence occur in the same mineral, their ratio to each other is constant, the compound being essentially a double salt. This principle is futher discussed in a

• Wherry, E. T., and Foshag, W. F., Classification of the sulphosalt minerals, Jour. Wash. Acad. Sci., vol. 11, pp. 1-8, Jan., 1921.

paper by Foshag which is now in press. The formula assigned to diaphorite by these authors in 4PbS.3Ag2S. 3SbS or with the ratio RS: Sb2S = 7:3. When this result was first submitted to the writer's attention it was thought possible that boulangerite might also have these ratios, the difference being small. The compositions to satisfy the two formulas are as follows:

An examination of the analyses published by the writer in the paper above cited shows that most of them agree most nearly with the first formula although one or two approach the second. The analysis of material from the specimen bearing the crystals here described agrees very closely with the 5:2 ratios which may not be significant as the analysis was made upon the fibrous portion of the specimen, the crystals not being sufficient in amount for analysis. The problem of determining the correct composition of boulangerite now seems further complicated by the probable existence of a lead sulphantimonite having 7:3 ratios. It is obvious that very exact analytical work on material of undoubted purity will be necessary to distinguish between these two compounds. Existing knowledge of the minerals diaphorite and boulangerite appears to indicate that they have different ratios of base to acid and hence fall in different groups, the crystallographic similarity being accidental and not significant. Any evidence as to the crystal form or physical properties of minerals of this general composition should be carefully recorded as such data may ultimately lead to the differentiation of two or more species.

ART. XXX.-The Oriskany Sandstone Faunule at Oriskany Falls, New York;1 by HARRY N. EATON.

During the course of faunal studies of the Oriskany of central New York it seemed advisable to visit the type locality at Oriskany Falls whence the formational name was derived. As the result of several days' collecting in July, 1919 a faunule was found which is probably representative, and is enumerated below.

Extent and Stratigraphy.

The sandstone outcrops in a bold ledge on the hillside on the northern outskirts of the village of Oriskany Falls at an elevation of about 1080 feet. This hill is a plateau spur pointed southward, broadening out to the north in the southern part of Oneida County; bounded on the east by the valley of Oriskany Creek, and on the west by the valley of Sconondoa Creek. The outcrop is nearly unbroken for a mile northward of the village in the Oriskany Creek valley, and thence northward there are no further exposures owing to the drift cover. On the western side of the hill it can be traced by a line of bowlders, rising gradually to an altitude of 1260 feet to a point about 1344 miles north of the village of Augusta, in harmony with the gentle southerly dip of the region. On account of the drift cover, the northern boundary of the formation is uncertain, but probably does not lie more than 3 miles north of Oriskany Falls. The greatest breadth east and west is about 134 miles.

The thickness was given by Vanuxem" as "about twenty feet," but Brigham's estimate of "about ten feet" is more in accord with the writer's measurements. Vanuxem's error was a natural one to make at the outcrop nearest the village, as at this place a row of large sandstone blocks has been plucked away from the parent ledge and moved a few feet downward so as to give the formation a double apparent thickness.

The Oriskany sandstone at this locality lies directly upon the Helderberg limestone,-or Manlius according

The above paper was read before Section E, A. A. A. S., at St. Louis, Dec. 30, 1919. An abstract was published in Science, new ser., 51, 493, 1920. 'L. Vanuxem, Third Ann. Rept. Geol. Survey, Third Dist. N. Y., p. 273,

2

1839.

A. P. Brigham, The Geology of Oneida County, Oneida Hist. Soc., Trans., 1887-1889, p. 109, 1889.