Book of Mormon Geography

Above are two theories about the lands described in Alma 22 in the
Book of Mormon (http://scriptures.lds.org/en/alma/22).

27 And it came to pass that the king sent a proclamation throughout
all the land, amongst all his people who were in all his land, who
were in all the regions round about, which was bordering even to the
sea, on the east and on the west, and which was divided from the land
of Zarahemla by a narrow strip of wilderness, which ran from the sea
east even to the sea west, and round about on the borders of the
seashore, and the borders of the wilderness which was on the north by
the land of Zarahemla, through the borders of Manti, by the head of
the river Sidon, running from the east towards the west—and thus were
the Lamanites and the Nephites divided.
28 Now, the more idle part of the Lamanites lived in the wilderness,
and dwelt in tents; and they were spread through the wilderness on the
west, in the land of Nephi; yea, and also on the west of the land of
Zarahemla, in the borders by the seashore, and on the west in the land
of Nephi, in the place of their fathers' first inheritance, and thus
bordering along by the seashore.
29 And also there were many Lamanites on the east by the seashore,
whither the Nephites had driven them. And thus the Nephites were
nearly surrounded by the Lamanites; nevertheless the Nephites had
taken possession of all the northern parts of the land bordering on
the wilderness, at the head of the river Sidon, from the east to the
west, round about on the wilderness side; on the north, even until
they came to the land which they called Bountiful.
30 And it bordered upon the land which they called Desolation, it
being so far northward that it came into the land which had been
peopled and been destroyed, of whose bones we have spoken, which was
discovered by the people of Zarahemla, it being the place of their
first landing.
31 And they came from there up into the south wilderness. Thus the
land on the northward was called Desolation, and the land on the
southward was called Bountiful, it being the wilderness which is
filled with all manner of wild animals of every kind, a part of which
had come from the land northward for food.
32 And now, it was only the distance of a day and a half's journey
for a Nephite, on the line Bountiful and the land Desolation, from the
east to the west sea; and thus the land of Nephi and the land of
Zarahemla were nearly surrounded by water, there being a small neck of
land between the land northward and the land southward.
33 And it came to pass that the Nephites had inhabited the land
Bountiful, even from the east unto the west sea, and thus the Nephites
in their wisdom, with their guards and their armies, had hemmed in the
Lamanites on the south, that thereby they should have no more
possession on the north, that they might not overrun the land
northward.
34 Therefore the Lamanites could have no more possessions only in
the land of Nephi, and the wilderness round about. Now this was wisdom
in the Nephites—as the Lamanites were an enemy to them, they would not
suffer their afflictions on every hand, and also that they might have
a country whither they might flee, according to their desires.

See http://www.mormonhaven.com/bomgeog.htm