_GEOLOGY._
In accordance with the general results of Mr. G. K. Gilbert’s
investigation of recent earth movements in the Great Lakes region--that
the whole district is being lifted on one side or depressed on the
other, so that its plane is bodily canted toward the south-southwest,
and that the rate of change is such that the two ends of a line
one hundred miles long, running in a south-southwest direction,
are relatively displaced four tenths of a foot in one hundred
years--certain general consequences ensue. The waters of each lake are
gradually rising on the southern and western shores, or falling on
the northern and eastern shores, or both. This change is not directly
obvious, because masked by temporary changes due to inequalities of
rainfall and evaporation and various other causes, but it affects the
mean height of the lake surface. In Lake Ontario the water is advancing
on all shores, the rate at any place being proportional to its distance
from the isobase through the outlet. At Hamilton and Port Dalhousie
it amounts to six inches in a century. The water also advances on all
shores of Lake Erie, most rapidly at Toledo and Sandusky, where the
change is eight or nine inches a century. All about Lake Huron the
water is falling, most rapidly at the north and northeast; at Mackinac
the rate is six inches, and at the mouth of French River ten inches
a century. On Lake Superior the isobase of the outlet cuts the shore
at the international boundary; the water is advancing on the American
shore, and sinking on the Canadian. At Duluth the advance is six
inches, and at Huron Bay the recession is five inches a century. The
shores of Lake Michigan are divided by the Port Huron isobase. North
of Oconto and Manistee the water is falling; south of these places it
is rising, the rate at Milwaukee being five or six inches a century,
and at Chicago nine or ten inches. Eventually, unless a dam is erected
to prevent it, Lake Michigan will again overflow to the Illinois
River, its discharge occupying the channel carved by the outlet of a
Pleistocene glacial lake. The summit in that channel is now about eight
feet above the mean level of the lake, and the time before it will be
overtopped may be computed. For the mean lake stage such discharge will
begin in about one thousand years, and after fifteen hundred years
there will be no interruption. In about two thousand years the Illinois
River and the Niagara will carry equal portions of the surplus water
of the Great Lakes. In twenty-five hundred years the discharge of the
Niagara will be intermittent, failing at low stages of the lake, and in
thirty-five hundred years there will be no Niagara. The basin of Lake
Erie will then be tributary to Lake Huron, the current being reversed
in the Detroit and St. Clair channels.
_GEOGRAPHY._
Relating to the Royal Geographical Society the story of his exploration
of the Bolivian Andes, Sir Martin Conway spoke of his journey by way of
the Arequipa Railroad, Peru, to Lake Titicaca. That remarkable sheet
of water is fourteen times the size of the Lake of Geneva and twelve
thousand feet above the sea, and might be regarded as the remnant of
a far greater inland sea, now shrunk away. Driving from Chililaya, he
reached the snowy mountain called the Cordillera Real--the backbone of
Bolivia--which he had come especially to visit, and in the region of
which he spent four months. To the east the mountains fell very rapidly
to a low hill country and the fertile valleys that send their waters
to the river Beni. On the other side lay a high plateau, at a uniform
altitude of from twelve thousand to thirteen thousand feet, from which
the tops of low rocky hills here and there emerged. This plateau had
obviously been at one time submerged; evidence was plentiful that in
ancient times the glaciers enveloped a large part of the slopes that
led down to it from the main Cordilleras and reached down many miles
farther than now. In the immense pile of _débris_ left by the glaciers
deep valleys were afterward cut by the action of water, and into these
valleys the glaciers of a second period of advance protruded their
snouts, depositing moraines that could still be traced _in situ_ as
much as four or five miles below the present limit of the ice. Contrary
to the apparently general impression that the peaks of the Cordilleras
were volcanic, the author had not been able to find any trace of
volcanic action along the axis of the range. The Cordillera Real had
been elevated by a great earth movement, and the heart of the range
consisted of granites, schists and similar rocks. The whole range might
be described as highly mineralized. Gold was found at several points,
but the chief auriferous valleys were those on the east side of the
range. Just below the snowy mass of Cacaaca on the west was a really
enormous vein of tin; and antimony, cobalt and platinum have been found
in different parts. The great copper deposits were not in this range,
but farther west. The flora of the high regions of the Cordillera
Real was apparently sparse, but is probably more abundant in the
rainy season. Bird life was more prolific and birds were numerous, at
suitable places, up to an altitude of seventeen thousand feet above the
sea.
_ZOOLOGY._
The most recent elementary text-book in zoölogy is from the press of
The Macmillan Co. Professor and Mrs. Charles B. Davenport are the joint
authors. It is recognized now-a-days that what the general high school
or elementary student in zoölogy needs is not professional training
in that subject, but rather an opportunity to view the field so that
he may have as wide an acquaintance as may be of the forms of animals
and of their doings. This he needs that he may have an interest in
the things of nature and that he may be a more intelligent member of
society in the things pertaining to his welfare as affected by animals.
The book is therefore an attempt to restore the old natural history
in a newer garb. The text is divided into twenty-one chapters. The
first of these deals with ‘The Grasshopper and its Allies,’ followed
by others upon the butterfly, beetle, fly, spider, etc., similarly
treated. Each chapter has one or two ‘keys’--that is, arrangements
whereby the families of animals may be determined. The book is richly
illustrated by means of half-tone and line reproduction; a number of
photographs are from life, and one of these is a flash-light photograph
of a slug and an earthworm crawling upon a pavement at night! Outlines
for simple laboratory work and a list of books dealing with the
classification and habits of American animals are to be found in an
appendix. Many good things might be said of this contribution to
zoölogical text-books. This ought to be said, that it will be a book
which will be of value to any person who, while upon his holiday trip,
wishes to learn about the animals he may come across.
_ORNITHOLOGY._
Mr. Chapman is equally at home with camera or pen. In ‘Bird Studies
with a Camera, with Introductory Chapters on the Outfit and Methods
of the Bird Photographer,’ he gives us some of his many experiences
from Central Park to the swamps of Florida and the bare rocks of the
Gulf of St. Lawrence. The first two chapters are devoted to a brief
discussion of the outfit and methods of the bird photographer, and
these any one thinking of taking up this branch of art will do well
to read carefully. Mr. Chapman considers that a 4×5 plate is the size
best adapted for general purposes, and notes that while a lens with
short focus may serve for photographing nests and eggs, for the birds
themselves a rapid lens with focus of fourteen to eighteen inches
should be used. The rest of the book is for the general reader, and
contains many facts of interest concerning the haunts, habits, and home
life of a number of birds from the well-known sparrow to the unfamiliar
pelican, the accounts of the Bird Rock and Pelican Island being the
most interesting. Some of the illustrations are a little disappointing,
and emphasize the difficulties of photographing wild birds, but
there is ample compensation for these in the excellence of others,
particularly those devoted to Percé, Bonaventure and Bird Rock. This is
equally true of birds and scenery, the views of Percé Rock being the
finest that have fallen under our notice. Mr. Chapman’s estimate of the
feathered population of Great Bird Rock, which he puts at 4,000, is by
far the smallest yet made, and probably has the soundest basis, and
shows a sad diminution from the hosts of fifty years ago.
* * * * *
‘Bird Homes,’ by A. Radclyffe Dugmore, seems well adapted for its
stated purpose of stimulating the love of birds, helping the ordinary
unscientific person to get some closer glimpses of them, and aiding
in the study of their wonderfully adapted nests and beautiful eggs.
Furthermore, it will probably create a strong desire in the reader to
become a photographer of birds and their nests. To further these aims
we have a first part containing half-a-dozen chapters devoted among
other things to birds’ nests and eggs, photographing nests and young
birds and the approximate dates when birds begin to nest, this being
adapted to the vicinity of New York.
Following this is the bulk of the volume, containing brief descriptions
of the birds, their nests, nesting places and eggs, and here the author
has confessedly borrowed from Bendire, Davie and other well-known
authorities, although one might wish that Mr. Dugmore had introduced
more of his own observations, since those given incidentally in the
first part are very interesting; where he indulges in theory he is
less successful. In place of the usual method of studying the nest
from the bird, we have that of studying the bird from the nest, and
for this purpose the nests are grouped in classes, a chapter being
devoted to each class; thus we have nests open, on the ground in open
fields, marshes and generally open country; open nests in trees; nests
in bridges, buildings, walls, etc. By this plan any one finding a nest
can, with a little care and observation, identify the bird that made
it. The illustrations, largely of nests and eggs, are a noteworthy
feature of the book, although the three-color process which succeeded
so admirably in Dr. Holland’s _Butterfly Book_, is here as equally
distinct a failure, the least bad of the colored plates being that
showing the nest of the yellow-breasted chat, the worst that of the
nest of the Baltimore oriole. Those in black and white, however, merit
the highest praise, and this includes the smaller cuts introduced as
decorative features in the first portion of the book. It would seem
difficult in a half-tone to improve on the plate of young crested
flycatchers for clearness of detail, while among others that deserve
special mention for artistic effect is the wood thrush on nest, and
the nests of the chestnut-sided, yellow, blue-winged and worm-eating
warblers. The general ‘get-up’ of the book is excellent, and the
printing of the plates separately permits the use of a deadfaced paper
for the text, which is pleasant to the eye.