Results 151 to 160 of about 671 (189)

Stromatoporoids: a beginner's guide

Geology Today, 1988
Stromatoporoids are an important group of fossil sponges that form some of the largest reef complexes in the fossil record and are valuable in palaeoecological and facies analysis. They are frequently large and easily studies in the field and in hand specimen.
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Cyanophycean nature of stromatoporoids

Nature, 1976
STROMATOPOROIDS are calcareous fossils abundant in many Palaeozoic (mainly Silurian and Devonian) shallow-water carbonate sediments. Forms ascribed to stromatoporoids have also been reported from Mesozoic epicontinental and tethyan carbonate deposits1.
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Original mineralogy of ordovician stromatoporoids

Carbonates and Evaporites, 1993
Stromatoporoids in the Middle Ordovician Yeongheung Formation show delicate reticulate structures of persistent laminae and discontinuous pillars. Abundant microdolomite inclusions are found in the stromatoporoid skeletons. Coexisting aragonite precursor grains such as gastropod and cephalopod preserve no internal microstructures due to extensive ...
Chan Min Yoo, Yong Il Lee
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The relationship of the stromatoporoids to the sclerosponges

Lethaia, 1972
Similarities of the extinct strornatoporoids to the sponges of the recently established order Sclerospongia have strengthened arguments that these fossils are closer to the Porifera than to the Coelenterata. Major features favouring the affinity of the stromatoporoids to the sclerosponges include: (1) lack of evidence of colonialism in the ...
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Stromatoporoids: Internal Morphology

Notes for a Short Course: Studies in Geology, 1983
There are two levels at which the internal structure of a stromatoporoid is classified. The first level includes structures which can be discerned in a thin section using low magnifications (10X); these are called macrostructures. The second level is composed of structures that are not evident unless a thin section is magnified to a higher degree (50X ...
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Biogeography of Ordovician stromatoporoids

Palaeogeography, Palaeoclimatology, Palaeoecology, 1980
Abstract This paper reviews the distribution of stromatoporoids in relation to Ordovician geography. The labechiids were the first of the three Ordovician families to make their appearance. They became established in well-circulated, shallow, subtidal, equatorial waters of the open shelf during the Late Llanvirn-Llandeilo (North American Chazyan ...
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A Devonian Stromatoporoid Reef

American Midland Naturalist, 1931
True reefs-as distinguished from massive beds-formed by stromatoporoids and stromatoporoid detritus have been recorded infrequently. Thus Cumings and Shrock, in their discussion of Niagaran reefs,2 do not stress the importance of these organisms in the building of reefs, even though they describe one reef whose central mass, or "core rock is a breccia ...
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Stromatoporoids: Geologic History

Notes for a Short Course: Studies in Geology, 1983
The great majority of the published work on the paleontology of the stromatoporoids has appeared since 1950. This influx of information has made possible a fairly clear picture of their evolution. As mentioned earlier by Stearn, stromatoporoids were quite abundant in shallow marine environments from the Middle Ordovician through the Late Devonian ...
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Biogeography of Silurian stromatoporoids

Geological Society, London, Memoirs, 1990
Abstract Stromatoporoids were widespread in the Ordovician, Silurian and Devonian shallow seas with carbonate types of sedimentation. Their occurrences in reefs and association with bahamitic type carbonate sediments, sometimes replaced by evaporites, allow them to be considered as stenothermal warm-water organisms which lived in the tropical
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Intracoenosteal variation in a Devonian stromatoporoid

Lethaia, 1973
Fagerstrom, J. A. & Saxena, K. M. L.: Intracoenosteal variation in a Devonian stromatoporoid. Statistical analysis of four different features of coenosteal morphology measured in sixteen randomly distributed vertical and tangential thin sections from a specimen of Syringostroma sherzeri (Grabau) from the Detroit River Group near Ingersoll ...
John Alfred Fagerstrom, K. M. Lal Saxena
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