Date of Award


Degree Type


Degree Name

Doctor of Philosophy




Dr. Cameron J. Tsujita

Second Advisor

Dr. Jisuo Jin

Third Advisor

Dr. Alfred C. Lenz


The late Middle Devonian (Givetian) Hamilton Group of southwestern Ontario is well known worldwide for its diverse, abundant and well-preserved brachiopod fauna. Yet, despite their undoubted value as a paleontological resource, the Hamilton Group brachiopods have been largely ignored over the past few decades in terms of their systematics and potential biostratigraphic value. A detailed systematic study of brachiopods collected from exposed strata of the Hamilton Group in the Arkona-Thedford-Ipperwash area of southwestern Ontario has led to the recognition of 50 species assigned to 34 genera, among which one species, Devonochonetes arkonensis n. sp., has been newly defined. A quantitative study of 38 brachiopod associations from the Hamilton Group of southwestern Ontario and equivalent strata in the Appalachian and the Michigan basins, using Q-mode (taxa as variables) and R-mode (localities/ages as variables) cluster analyses, principal component analysis, and four faunal similarity analyses (i.e., Jaccard similarity, Dice similarity, Simpson’s coefficient of similarity, and Raup-Crick similarity indices), has revealed that the late Middle Devonian (Givetian) brachiopod faunas from time-equivalent strata of the Michigan and Appalachian are distinct, al lowing identification of two separate faunal subprovinces. In spite of its present-day position in the southeastern part of the Michigan Basin, southwestern Ontario had brachiopod associations which were more similar to those in contemporaneous strata of the Appalachian Basin during the deposition of the lower and middle Hamilton sediments. This may have been related to the absence of a 111 topographie high in the present-day Findlay Arch area that would have otherwise prevented immigration of Appalachian Basin fauna into the study area. During the deposition of the upper Hamilton strata, the southwestern Ontario brachiopod associations developed a closer affinity to those of the Michigan Basin, suggesting that the immigration of brachiopod faunas from the Appalachian Basin into the study area was impeded. This change in faunal affinity may have been related to the formation of a local arch at present-day Cleveland area of Ohio that blocked the immigration of Appalachian Basin taxa into the study area.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.