The dominantly transgressive Upper Silurian interval of the Keyser Limestone (U. Sil. - L. Dev.) in the central Appalachians has yielded the most diverse fauna of rhombiferan cystoids found in any single formation in North America. All forms are members of the Callocystitidae, a diverse family of the Glyptocystitida. Nine lithofacies are recognized within this stratigraphic interval, representing all major epeiric sea environments from supratidal through shallow shelf below wave base. Identification of cystoid genera and species by disarticulated part studies (comparison of isolated plates to the corresponding element on whole thecae of known taxa) demonstrates their restriction to three discrete assemblages on the open shelf.
Cystoid bearing lithofacies represent a contemporaneous and laterally coexisting sequence of skeletal sands and silt which include: 1. well sorted calcarenite (both biosparudite and biosparite), 2. poorly sorted biosparite, 3. open shelf (fossiliferous) calcisiltite. Maximum cystoid diversity is recorded in the calcisiltite, diminishing progressively in coarser shoreward calcarenites. Callocystitid distribution is suggested to have been primarily depth controlled. These cystoids were intolerant of turbid water, high sedimentation rate and of high energy nearshore sands and infirm mud bottoms. A new genus Laosacystis monterey is described and assigned to the subfamily Staurocystinae on the basis of its four protuberant ambulacra. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Stephenson-Supplemental-1974.pdf
| Identifer | oai:union.ndltd.org:TEMPLE/oai:scholarshare.temple.edu:20.500.12613/8431 |
| Date | January 1974 |
| Creators | Stephenson, David Charles |
| Contributors | Anderson, E. J. (Edwin Joseph), 1939-, Goodwin, Peter W. |
| Publisher | Temple University. Libraries |
| Source Sets | Temple University |
| Language | English |
| Detected Language | English |
| Type | Thesis/Dissertation, Image |
| Format | 105 pages |
| Rights | IN COPYRIGHT- This Rights Statement can be used for an Item that is in copyright. Using this statement implies that the organization making this Item available has determined that the Item is in copyright and either is the rights-holder, has obtained permission from the rights-holder(s) to make their Work(s) available, or makes the Item available under an exception or limitation to copyright (including Fair Use) that entitles it to make the Item available., http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | http://dx.doi.org/10.34944/dspace/8395, Digital copy of print original., Theses and Dissertations |
Page generated in 0.0021 seconds