These journals cover most of the two journeys between California and the Rocky Mountains led by Jedediah Smith, of the Smith, Jackson, and Sublette company in 1826-28.
The journal of the first expedition was included in: Brooks, George R., The Southwest Expedition of Jedediah S. Smith, published 1977, Authur H. Clark Company.
The journal of the second expedition was included in: Sullivan, Maurice S., The Travels of Jedediah Smith, published 1934, Fine Arts Press, Santa Ana.
These books provide valuable introduction and notes along with Smith's journals. The on-line version provided here includes only Smith's original text.