The type section of the Morrow Series, Lower Pennsylvanian, in Washington County, Arkansas, contains an abundant marine and land fossil record in a relatively undisturbed stratigraphic sequence--a combination not found elsewhere in thicker and more complete sections of Early Pennsylvanian age. The type Morrow lies within a similarly

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varied and relatively undisturbed sequence of fossiliferous formations of Mississippian, Pennsylvanian, and Early Permian age that are overlapped like shingles from the Ozark uplift to central Oklahoma and Kansas. These properties have made the type Morrow and adjacent series a standard of reference for late Paleozoic stratigraphy. The term Pennsylvanian was first applied by H. S. Williams, 1891, in Washington County.

The type Morrow consists of marine clastics and limestone and minor units of terrestrial clastics and coal. The sedimentary content and structures are marked with the usual channeloid deposits and lateral variations that are to be expected on a marine shelf subjected to interrupted sinking, variations in sea level, and beginnings of heavy, Pennsylvanian alluviation from the north. Lateral variations pose numerous problems in mapping Morrow units outside the type area.

Secondarily enlarged quartz sand is abundant. The source of the free silica is a problem, considering the seeming maturity and recycled nature of the original Morrow sediments together with the evidence against outside sources or hydrothermal action, the extreme rarity of chert, and the normal occurrence of silica-fixing organisms. The suggested source is diffused ash, but the only direct evidence for ash is a small area of chalcedony that lacks shards but resembles the seat rock of bentonite beds. The diagenesis of supposedly magnesian calcite shells of Ottonosia, Osagia, and sedimentary Cornuspiridae is suggested as the cause for exfoliation of the Kessler Limestone Member of the Bloyd Formation. Interpenetration of ooliths by micrstylolitic action gives a measure of shrinkage in some limestone beds and suggests the cause for "bread crumb" textures in some limestones. The abundant spoor of arthrophycids and Conostichus in the Hale Formation and of Scalarituba, Laevicyclus, and Taonurus in the Atoka show that these fossils are not necessarily indicators of deep, barren, marine bottoms, as some specialists on flysch deposits have urged.

LLOYD G. HENBEST

Lloyd G. Henbest, U.S. Geological Survey, was born on a farm 5 miles south of Cassville, Missouri, January 9, 1900. He claims that his first geologic employment began at an early age behind the plow, tilling refractory, flinty soil derived from Mississippian chert.

After graduating at the University of Arkansas in 1924 and at the University of Kansas in 1927, Henbest became an assistant of G. H. Cady on the Illinois State Geological Survey in 1926. In 1928, he served as a consultant of the Mississippi Coal Corporation; married Fanny M. Ross, concert pianist; and the same year began graduate study at Yale where with Carl O. Dunbar he published "Pennsylvanian Fusulinidae of Illinois". In 1930, he joined the U.S.G.S. as an assistant of J. A. Cushman for work on Foraminifera. On the U.S.G.S. his interests have also included general problems in historical geology, and numerous publications have resulted.

He is past-President and a founder of the Cushman Foundation for Foraminiferal Research. In 1954, he received the SEPM award for the best paper in the Journal of Paleontology; in 1956 the citation of Distinguished Alumnus of the University of Arkansas; and in 1959, the Haworth Citation, University of Kansas. He has given more than 30 shows of pictorial photographs before audiences of the National Park Service and various art, photographic and other societies.

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