Abstract

Four lithosomes are identified: A, the thinned eastward extension into the study area of the Tully Limestone; B, above A and coextensive with the eastern extension of the Genesee Shale, very dark fissile shale grading eastward into shaly siltstone; C, a clastic wedge which envelops A and B, of siltstone and fine-grained sandstone with much sedimentary structure preserved; and D, red and green siltstone and mudstone with immature sandstone interbedded. Tully sedimentation occurred during a transgression; terrigenous material was trapped east of a submarine topographic high, thus permitting carbonate deposition in an otherwise clastic basinal area. Landward migration of the strandline resulted in more widespread estuarine conditions. The rising sea level caused alluviation of fine-grained sediments in entering streams, resulting in greater quantities during Tully time than before or after.

First Page Preview

First page PDF preview
You do not currently have access to this article.