26 T. STERRY HUNT ON THE GENETIC 
and banded, and evidently concretionary, but sometimes so finely granular and homoge- 
neous in portions as to be quarried for architectural purposes, like the indigenous gneisses 
of the series, which they often closely resemble. Remarkable examples of the same phe- 
nomenon are to be met with in the older gneissic or Laurentian series, some of which are 
conspicuous in the sections of these rocks visible in the cañon of the Arkansas River, 
and elsewhere in Colorado. Still more striking examples are met with in the similar 
gneisses in parts of Canada, and are well displayed in Ottawa county, in the province of 
Quebec, where, in the township of Buckingham, veins eighty feet in breadth, and made 
up almost wholly of orthoclase and crystalline cleavable magnetite, traverse for consider- 
able distances the stratified gneiss of the region. ' 
§ 45. In the same county, and near the Riviere aux Liévres, are the great veins 
which have lately been extensively mined for apatite in what is known as the Liévres 
district. Very similar veins also occur a short distance to the southwest, along the Rideau 
canal, in the province of Ontario, in what may be called the Rideau district. The veins 
in this latter area were first described by the writer as early as 1848, and subsequently 
in 1863, in 1866, and in 1884.” The history of these apatite deposits in the two districts, 
which may be considered together, will serve to illustrate some important facts in the 
theory of crystalline rocks. The principal associates of the apatite in these districts are 
pyroxene, phlogopite, orthoclase, quartz, calcite, and pyrite. It was said of the localities 
in the Rideau district, in 1863, that a careful examination in each case shows that “the 
deposit occurs in a fissure in the stratification, and has well-defined walls,” while “a 
banded arrangement of the mineral contents is often very well marked ;” —the various 
minerals named sometimes, occurring in alternate layers, of which the calcite, often with 
included apatite crystals, has “the aspect of a coarsely crystalline lamellar limestone.” 
Farther examples were then given, showing the bilateral symmetry in many of the veins, 
and the occasional presence in them of drusy cavities. Moreover, although small portions 
of apatite were observed in what were regarded as the limestone beds of the enclosing 
gneiss, it was said that “the workable deposits of apatite, with few if any exceptions, are 
confined to the veinstones.” Such were the conclusions announced by the writer as late 
as 1866. Subsequently, in 1884, after farther studies of the Rideau district, he was led to 
write that although the deposits of apatite are in great part in true veins cutting the 
strata, and sometimes including angular fragments of the wall-rock,—which is the char- 
acteristic red or gray gneiss of the country,—they are “in part bedded or interstratified 
in the pyroxene-rock of the region.” With regard to certain apparently bedded deposits 
of apatite it was farther said, “ I am disposed to look upon [them] as true beds, deposited 
at the same time with the enclosing rocks,” which were described as “chiefly beds of 
pyroxene-rock, generally pale green or grayish-green in color, with mixtures containing 
quartz and orthoclase, and distinctly gneissoid in structure.” 
$ 46. I am careful to emphasize this apparent contradiction between the assertion 
of the truly endogenous character of the deposits in which apatite occurs with pyroxene, 


? Geol. Survey of Canada, Report for 1848, p. 132, and for 1863-66, pp. 224-229; also Geology of Canada, 1863, 
pp. 461, 592, 761, and Trans. Amer. Inst. Mining Engineers, 1884, vol. xii, pp. 459-468. See farther, B. J. Harring- 
ton, Report Geol. Survey of Canada, 1877-78, G., pp 1-36, and J. Fraser Torrance, Jbid., 1882-83-84, J., pp. 3-30, for 
yaluable contributions to our knowledge of the Canadian apatite deposits. 
