Assuming academic writing as a genre-specific discourse which is linguistically and socio-culturally embedded both in the wider academic discourse community and the local context where it is produced, the present study sought to investigate Saudi EFL undergraduate students' use of cohesive devices as a text-forming resource in the creation of argumentative essays. More specifically, the study attempted to explain the use of cohesion in the creation of texture, and in the rhetorical structure of the sample texts. Structured questionnaires and interviews were also used to gauge the perceptions of the teachers and the students about the teaching and learning of academic writing and cohesive devices, and to triangulate the study. The researcher adopted a mixed-methods approach for analysis of the data. Halliday and Hasan's (1976) model of cohesion analysis was the mainstay of the data analysis; however, frameworks from other perspectives such as the Systemic Functional Linguistics, English for Specific Purposes, Academic Literacies, and English Language Teaching were also consulted to find out answers to the three research questions of the study. The results obtained through quantitative and qualitative analysis of the data revealed that cohesive devices were statistically significantly correlated with the text length and sentence units. However, they varied significantly between two extremes of the text length. The appropriate use of cohesive devices was also significant as the non-significant misuse or overuse did not affect the texture or Exam/cohesion scores of the sample texts. The study also claims that cohesive density rather than the text length was the significant variable of differences in the Exam and cohesion scores for the texts. Referential and lexical cohesion appeared to be statistically significant, and thereby the most preferred cohesive devices in the
corpus. The pattern of texture in the students' essays corresponded with Halliday and Hasan's (1976 p.296) notion of 'dense texture'. The study also claims to be the first initiative of its kind to have analyzed cohesion in the rhetorical structure of the argumentative essays. The move analysis revealed significant correlations between the moves in the three stages of the sample texts. The survey questionnaires unfolded statistically significant dichotomies between the pedagogic and learning beliefs of the teacher and the student participants. I argue that cohesion is an important non-structural resource in the creation of texture; however, it provides only a partial picture. The students do use cohesive devices but with instances of misuse and overuse. Moreover, there is the need to help students make use of other types of reiteration, collocations and conjunctions for a better cohesive effect, and lexical and semantic diversity. The study recommends raising awareness and functional ability of the students through explicit teaching of cohesive devices not as discrete grammatical items but as discourse semantic resources of text formation
