Terrestrial geology and geophysics
Terrestrial geology and geophysics
Closure in Gondwanaland distribution of conchostracan genus Leala P. TASCH
Department of Geology Wichita State University Wichita, Kansas 67208
In a memoir recently published (Tasch 1987), a "note added in proof" was appended. It referred to information received from a colleague, Shekkar Chandra Ghosh, in the Geological Survey of India. He reported the fortuitous discovery of a leaiid fauna by the Coal Division (Geological Survey of India) during field work that included sampling the Pali Formation (Madhya Pradesh), central India. A Leaia zone some 2 meters thick had been uncovered in a small hillock in the red shale of the Upper Pali Formation (for prior Pali Formation data cf. Sastry et al. 1977). The formation contains a Glossopteris flora and is overlain by the Parsora Formation that has a Dicroidium flora. The age of the Pali Formation is Upper Permian. At the time that this note was appended there was little to go on beyond a series of sketches. Subsequently, rubber imprints of 60 individual specimens and photographs were sent for examination. Study of this collection led to the determination that these genera were present: • Leaia (Hemicycloleaia), • Rostroleaia,
• two incomplete specimens, • Cycloleaia (?) and Monoleaia (?), and
• Cyzicus (Euestheria).
The absence of Leaia in India had long puzzled me. Its occurrence in the other four southern continents and in the pre-
1988 REVIEW
Drift configuration of these continents, indicated that Leaia should occur there also. The new data on hand permit the statement with greater assurance that genus Leaia does occur in the late Paleozoic beds of India. In turn, that genus can be added to the other four genera (Palaeolimnadia, Estheriina, Cornia, and Cycles th erio ides), the species of which occur in the rock column of each of the five southern continents (Tasch 1987). Shen (1984) described several ribbed conchostracans of Upper Permian age from the Sunan Formation of China. Among others, he described Hemicycloleaia (= Leaia (Hemicycloleaia) and Rostroleaia. These same two genera, among other leaiids, are now known from the Pali Formation of India. Although the same two genera are known from the Kouznetsk Basin, U.S.S.R., they are in Lower Permian beds (Novojilov 1956). Was there a Chinese ribbed-conchostracan egg dispersal to India during Upper Permian time? Present evidence suggests the plausibility of that event. (Cf., Tasch 1987 for a Middle Devonian-Lower Carboniferous Australian-Chinese connection which also involves Leaia and Rostroleaia). The antarctic Ohio Range Leaia zone must now be placed in this enlarged context.
References Novojilov, N. 1956. Crustacean phyllopod bivalves. 1. Leaiidae, Moscow. Paleontological Institute, USSR. Trudy 61, 129. Sastry. M.V.A., S.K. Acharya, S.C. Shah, P.P. Satsangi, S.C. Ghosh, P.K. Raha, Gopah Singh, and R.N. Ghosh. 1977. Stratigraphic lexicon of Gondwana formations of India. Geological Survey of India. Miscellaneous Publications, 36, 71ff. Shen, Yan Bin. 1984. Occurrence of Permian Leaia conchostracans in China and its palaeogeographical significance. Acta Palaeontologia Sinica, 23(4), 505-512. Tasch, P. 1987. Fossil conchostracans of the southern hemisphere and continental drift: Paleontology, biostratigraphy and dispersal. (Geological Society of America, Memoir 165.)
Closure in Gondwanaland distribution of conchostracan genus Leala P. TASCH
Department of Geology Wichita State University Wichita, Kansas 67208
In a memoir recently published (Tasch 1987), a "note added in proof" was appended. It referred to information received from a colleague, Shekkar Chandra Ghosh, in the Geological Survey of India. He reported the fortuitous discovery of a leaiid fauna by the Coal Division (Geological Survey of India) during field work that included sampling the Pali Formation (Madhya Pradesh), central India. A Leaia zone some 2 meters thick had been uncovered in a small hillock in the red shale of the Upper Pali Formation (for prior Pali Formation data cf. Sastry et al. 1977). The formation contains a Glossopteris flora and is overlain by the Parsora Formation that has a Dicroidium flora. The age of the Pali Formation is Upper Permian. At the time that this note was appended there was little to go on beyond a series of sketches. Subsequently, rubber imprints of 60 individual specimens and photographs were sent for examination. Study of this collection led to the determination that these genera were present: • Leaia (Hemicycloleaia), • Rostroleaia,
• two incomplete specimens, • Cycloleaia (?) and Monoleaia (?), and
• Cyzicus (Euestheria).
The absence of Leaia in India had long puzzled me. Its occurrence in the other four southern continents and in the pre-
1988 REVIEW
Drift configuration of these continents, indicated that Leaia should occur there also. The new data on hand permit the statement with greater assurance that genus Leaia does occur in the late Paleozoic beds of India. In turn, that genus can be added to the other four genera (Palaeolimnadia, Estheriina, Cornia, and Cycles th erio ides), the species of which occur in the rock column of each of the five southern continents (Tasch 1987). Shen (1984) described several ribbed conchostracans of Upper Permian age from the Sunan Formation of China. Among others, he described Hemicycloleaia (= Leaia (Hemicycloleaia) and Rostroleaia. These same two genera, among other leaiids, are now known from the Pali Formation of India. Although the same two genera are known from the Kouznetsk Basin, U.S.S.R., they are in Lower Permian beds (Novojilov 1956). Was there a Chinese ribbed-conchostracan egg dispersal to India during Upper Permian time? Present evidence suggests the plausibility of that event. (Cf., Tasch 1987 for a Middle Devonian-Lower Carboniferous Australian-Chinese connection which also involves Leaia and Rostroleaia). The antarctic Ohio Range Leaia zone must now be placed in this enlarged context.
References Novojilov, N. 1956. Crustacean phyllopod bivalves. 1. Leaiidae, Moscow. Paleontological Institute, USSR. Trudy 61, 129. Sastry. M.V.A., S.K. Acharya, S.C. Shah, P.P. Satsangi, S.C. Ghosh, P.K. Raha, Gopah Singh, and R.N. Ghosh. 1977. Stratigraphic lexicon of Gondwana formations of India. Geological Survey of India. Miscellaneous Publications, 36, 71ff. Shen, Yan Bin. 1984. Occurrence of Permian Leaia conchostracans in China and its palaeogeographical significance. Acta Palaeontologia Sinica, 23(4), 505-512. Tasch, P. 1987. Fossil conchostracans of the southern hemisphere and continental drift: Paleontology, biostratigraphy and dispersal. (Geological Society of America, Memoir 165.)
