20 
lips gives two principles as the basis of Werner’s 
system: 
rt. ‘‘When two veins cross, and one of them. cuts 
through the other, the one which is divided is the more 
ancient.” 
2. “In effect, among superimposed stratified rocks, 
the lowest was deposited first and is the oldest.” 
Lehman, it seems, worked out these principles in 
part before Werner, but he fell short of his countryman 
in the extent of their application and significance. 
By the first of Werner’s laws, we determine not only 
the relative time of occurrence of veins and dykes, but 
also that of faults, joints, brecciation and other minu- 
tie in modern petrographical investigations with the 
microscope. In the same category of contact phe- 
nomena might also be placed unconformities, the im- 
portance and use of which have only within afew years 
been fully elaborated by the geologists of the Lake 
Superior district. 
The second of Werner’s generalizations is to strati- 
graphic geology what the first is to the study of igneous 
rocks and secondary structures. How these, to us 
seemingly obvious, laws are used in modern geological 
instruction and field investigation is seen by Professor 
Davis's paper on ‘‘ Instruction in Geological Investiga- 
tion” (in Am. Nat., xxi., 1887, pp. 810-825). One essen- 
tial advance is in recognizing what Hutton insisted on, 
the intrusive origin of the igneous rocks, and in inter- 
preting unconformities, but our method of diagnosing a 
field of outcrops or the structure of a mine is 
that which Werner pursued with his classes a century 
ago. 
HABITS OF THE PURPLE FINCH — COR- 
PODACUS PURPUREUS, GRAY. 
BY M. W. VANDENBURG, FORT EDWARD, N. Y. 
_ Tue pleasant articles contributed to Science by Dr. 
Morris Gibbs, on ‘‘Birds and Bird Life,” have re- 
awakened observations often made by me on the habits 
of this spirited little songster. Some of these habits 
are, in so far as I know, unique; others are rarely found 
in other species, while still others are common to many 
species. 
In its arrival from the south the purple finch often 
divides honors with the song sparrow, and pours forth 
from the top of some tall naked maple or elm sucha 
voluble, rattling, exuberant songit seems as if he must 
needs sing or burst. This, too, while fields are white 
and winds blowing keen. In ten days or so, the females 
appear in twos, threes or fours. In the little flocks, if so 
few as six to ten can be called a flock, every one goes 
as he or she pleases, though they always keep in sight 
of each other, or in hearing of the sharp ‘‘chick”’ call- 
note. 
Soon as the days grow mild, and snow leaves the 
fields, mating begins; and now comes the strange part 
of the story. The females sing as well as the males, 
and, what is more, the full round of the ‘‘set song.” 
That is, the purple finch has a full, regular song of a 
. certain number of notes (words), always repeated in the 
same order, and with very rare variations from this 
order. It is repeated very rapidly in a loud, high- 
pitched key, and ends very abruptly in the early spring 
song of the male, and always soin the song of the 
female. In the later spring song of the male, there fol- 
lows the loud song, a very soft tremulo strain contain- 
ing, it always seemed to me, a mimicry of the notes of 
SCIENCE. 
[Vol. XXIII. No. 57% 
other birds, among which one may detect one or two 
words from the pee-wee. This solto voce song finally 
dies out as if he had forgotten the last notes, and often 
ends with a little whistle. : 
The female never aspires to this part of the song. 
Her song is a signal for all the males to assemble, and 
then the rapid fighting begins. The female downs ~ 
fiercely every male who dares approach her, but is very 
lenient towards her own sex. So vicious and vigorous 
are her attacks that the male usually gives her a wide 
berth and keeps his eye quite as much on the avenue of 
escape ason her comely figure. This is no mistake of 
mine. It is not the song of animmature male. 
And this is why I know I am correct. — For several 
years | had a pair of these birds in a cage, where they 
were reared from the time they left the nest. On the 
approach of spring, say about the last of February or 
first week in March, the birds became very restless. 
They both began to sing; they grew very quarrelsome 
and constantly indulged in the fiercest brawls. Wilson 
says: ‘‘They appear to be of a tyrannical and domineer- 
ing disposition,’ and not an hour passed in the day that 
did not demonstrate the correctness of this observa- 
tion. 
From being perfectly peaceful and considerate of each 
other, they grew so quarrelsome, so persistently pug- 
naceous, that they disturbed the whole household, and 
often the cage had to be covered over to lessen the 
bickering. In these first days of war the female was 
always victor, and she was wholly merciless. Later on 
her courage gradually failed, and by the end of a month 
or six weeks they ceased to fight, the male having won 
the day. He would ‘“‘boss the household” fora week or 
two, with a pretty firm hand of authority, but not until 
many a well-fought field had been lost and won for days 
and days in succession. 
They could never be pursuaded to build a nest. The 
female would lay from three to four eggs in the cage 
bottom. For one or two seasons a second laying suc- 
ceeded, but this was not usual. 
In the wild state the male never approaches the nest. 
He alights on a tree six to ten rods away and rapidly 
sings his full, loud song once or twice. The female 
answers him with a low call-note, leaves the nest and he 
feeds her from his ‘‘crop” in the same manner as the 
yellow-bird feeds its young. This done, he takesa 
hurried leave, and she-returns to the eggs. 
When the young first hatch this process continues, 
and the mother feeds them from her own crop, after 
being supplied by the male. Later on the male seems 
to forget his family altogether, or to feed the mother 
rarely and at a greater distance from the nest. ; 
In the end, the whole care of the family seems to de- 
volve on the female, and the ungracious sire never 
recognizes in any way his legitimate offspring. 
I do not know whether the female sings previous to 
the second nesting or not, but would think it probable 
that such was the case for a few days at least. 
Ihave met with unmated females singing as late as 
May or the first of June. The mated female, who no 
longer tolerates such giddiness and waywardness in a 
sister, pursues the singer with all the vim and vicious- 
ness she can command. 
The male, too, not infrequently comes in for a bluff 
rebuke, if he isnot discreet in his attentions to the coy 
spinster. 
Such have been my observations of the purple finch, 
extending over a period of thirty years. They are in 
the main correct, as it seems to me, for they have re- 
ceived confirmations during every year of that time. 
