50 GUIDEBOOK OF THE WESTERN UNITED STATES. 
much larger than it is at the present time. The increased volume of 
water in Apple Creek was due to the fact that it received a large part 
of the drainage of the ice sheet that piled up the Altamont moraine. 
Much of the clay, sand, and gravel washed out from the ice was carried 
down to Missouri River and swept southward by its mighty current, 
but a large amount was dropped along Apple Creek, filling the valley 
to a considerable depth. Since the disappearance of the ice the 
stream has cut a channel in this material 70 or 80 feet deep. The 
uplands on both sides of the valley of Apple Creek have only a thin 
veneer of glacial drift. (See footnote on p. 54.) 
The great amount of cutting done by Apple Creek when it was 
flooded by water from the melting ice is shown by the width of its 
flood plain where the valley joins that of Missouri River. At the State 
penitentiary 2 miles east of Bismarck the valley of Apple Creek has a 
changes its course and they were forced 
forks of the Missouri Sacajawea remem- 
bered the country and saw the spot where 
she had been captured many years be- 
fore. The expedition proceeded up Jef- 
ferson River to its head and crossed the 
Continental Divide (at Lemhi Pass) into 
Idaho. Here they met the Snake In- 
dians, Sacajawea even finding her brother 
and sister, but after a efforts they 
decided that it was to make 
their way down Sabsicn River to a Co- 
lumbia, so they turned northward, cross- 
ing the , and followed down 
the Bitterroot Valley until on September 
10 they came within 8 miles of the place 
where Missoula, Mont., is now situated. 
Here they turned to the left up what is 
now known as the Lolo trail and crossed the 
Cceur d’Alene Mountains, arriving at the 
mouth of Snake River October 16. From 
this point they rapidly drifted down the 
Columbia to the Pacific Ocean and went 
into winter quarters December 7 in a 
stockade which they named Fort Clat- 
sop, near the site of Astoria, Oreg. 
until March 23, 1806, when hed left Fort 
Soe on their eastward j : 
The party returned over peatticalty the 
same route to the Bitterroot Valley, where 
it was divided, Capt. Lewis making his 
way by Missoula and up Blackfoot River, 
along the route followed by the Indians 
in going to the plains to hunt buffalo, and 
Capt. Clark going back to the head of 
Jefferson River to recover their canoes, 
which had been cached at that place. 
Capt. Lewis crossed the Continental Di- 
vide at Lewis and Clark Pass and then 
made an attempt to explore the pass at 
the head of Marias River (now utilized 
by the Great Northern Railway), but 
trouble with the Indians prevented him 
from reaching the mountains, so he em- 
barked on the Missouri and floated down 
to the mouth of the Yellowstone, where 
the two parties were to meet again on 
their homeward journey. 
Capt. Clark crossed through the Big- 
hole country and, after getting the boats, 
floated down Jeffeteon River to Three 
Forks, where his party again divided, 
some going on down Missouri River to 
join Lewis, while Capt. Clark and a few 
others, including the faithful a 
as guide, started across the c 
Yellowstone River. They atte 
mouth of Tongue River 
ae City) on July 29 and the mouth 
of Yellowstone River August 3. They 
were slightly ahead of Capt. Lewis and 
© party was not united until August 
12, when they all came together at the 
mouth of Little Knife River, N. Dak. 
The rest of the journey was uneventful 
— they reached St. Louis September 
23, 1806. 
RE OE ES nag enn nO ae ee ee 
