Jean Baptise
Charbonneau (nickname Pompy which was given to him by William
Clark) was the first child of Sacagawea, a 16 year old Shoshoni girl who had been captured from her people years earlier by a tribe of natives called the Minnetarees.
To obtain her services Lewis and
Clark hired her husband
Toussaint Charbonneau as interpreter. Lewis and
Clark also allowed Sacajawea to bring her child Jean
Baptiste Charbonneau.
William
Clark made a promise to
Toussaint and Sacajawea to send young Jean to school. In 1810
Charbonneau and Sacajawea brought Jean
Baptiste to William
Clark who took charge of the youngster and put him in school.
In 1824 Jean
Baptiste met visiting
German Prince Paul of Wurttenberg and traveled with him in
Europe. Eventually he became an interpreter and guide among the Indians; one of the white men he later guided was Clark's own son
Jefferson.
He died in
Oregon in 1885 at the age of 80. There is a popular belief Sacajawea lived to the age of 100 and died in Wind River country of central
Wyoming, more substantial evidence points to a much earlier death.
Toussaint lived to old age, eventually vanishing from the prairies of
Upper Missouri, where he served as Government interpreter among the Mandans.
(a lot of this information came from the National Geographic Book "In the Footsteps of Lewis and
Clark" by Gerald
Snyder.)
As for Mary Brown who was 1/4 Indian if I was to take a guess I believe that it is very likely that she was the daughter of Jean
Baptiste. Also trying checking with the Western Shoshoni Indians of
Wyoming.
If I can find more information I will post it.