saluk mount is selected for devonian biostratigraphy. this area located at southwest of bojnurd. in this study three sections are selected and two sections, chahar-borj and tabar sections with a thickness of 650 m, which consist mainly of calcareous sediments was studied in detailed but third section, qelli section, with a thickness of about 450m which consist mainly of sandstone and evaporates was only described. conodonts are used to biostratigraphic study of saluk mount. for devonian biostratigraphy 80 conodont samples are examinied and 15 genera, 63 species, subspecies and morphotype from two sections was determined. all conodont taxt, have been reported for the first time from saluk mount and 1 genus and 22 species, subspecies and morphotype was reported for the first time from iran. one new species is found in this research. other organisms consist of brachiopods, fish remains and scolocodonts. stratigraphic distribution of conodont taxt was compared with modem standard conodont tables and three conodont biozone in tabar section (emisian to lower frasnian) and three conodont biozone in chahar-borj section (farmennian) was recognised. eifelian conodonts was not found in the study area. regional occurrences of conodont taxa showes more similarity with north america and europian conodonts and are less similar with australian conodonts. lithology and conodont taxa in tabar and chahar-borj sections are similar to khoshyeilaq formation. althought geological map of bojnurd at scale of 1.000.000 and 1.00.000 was published by geology survey of iran but lower carboniferous strata, was not reported. in this thesis for the first time lower carboniferous sediments from bojnurd geological map, chahar-borj section, have been reported. an assemblage of conodonts was found on the rock surface. it is for the first time that one assemblage of conodonts have been reported from iran. colour alteration index of conodonts was detetmined between 1.5-2, and predicted temperature ranges between 50 -140 for the area. paleocological studies on the basic of the conodonts in tabar and chahar-borj sections indicated shallow marin shelf environment.