Limestone Ledges Research Articles

Stratigraphic and Paleoenvironmental Studies on the Lower Eocene Succession at El-Guss Abu Said Plateau, Farafra Oasis, Western Desert, Egypt

Abstract The Lower Eocene Succession at El-Guss Abu Said Plateau was examined to determine the paleoenvironments and nature of deposition based upon benthic foraminiferal biofacies. Lithostratigraphically, this succession consists of the Esna Formation (shale) at the base, the Nusf Formation (well-bedded marl with occasional limestone ledges), and the Farafra Formation (limestone) at the top. The Esna Formation is an outer shelf-upper bathyal facies rich in planktonic and deeper-dwelling smaller benthic foraminifera. The Nusf Formation and the Farafra Formation are rich in Nummulites and Alveolinids, indicating a carbonate platform facies. Three benthic foraminiferal biofacies, combined with the lithology of the rock units, indicate progressive shoaling, likely associated with tectonic uplift that occurred during the early Eocene in the El-Guss Abu-Said area.

Ypresian Nummulites and their stratigraphic significance from El-Guss Abu Said plateau, Farafra Oasis, Western Desert, Egypt

El-Guss Abu Said plateau lies on the western scarp of Farafra Oasis. The studied succession consists of Esna Formation (shale) at the base, which is overlain by well-bedded alveoline marl (Nusf Formation) with occasional limestone ledges rich in nummulitic fauna. This unit ends with varved-like thin beds of marl and limestone before it is truncated by limestone unit of the Farafra Formation (limestone). Esna Formation is deep shelf facies as it is rich in planktonic foraminifera that assign it to Early Eocene in age. The first occurrence of nummulitic fauna was recorded in the lower part of Nusf Formation. Two species of Nummulites were identified; Nummulites solitarius de la Harpe 1883 and Nummulites fraasi de la Harpe 1883. These two species date this unit to Early Eocene time (Ypresian) that ranges from SBZ5 to SBZ6 of the standard Serra-Kiel et al., 1998, shallow benthic zonal scheme. The shift from deep shelf facies of Esna Formation to the carbonate platform facies of Nusf and Farafra Formations could point to a tectonic uplift that occurred in Early Eocene time.

A PORTRAIT OF MY FATHER IN SEVEN MAPS

1 5 R A P O R T R A I T O F M Y F A T H E R I N S E V E N M A P S D A V I D B A K E R 1. Here I heard them. Here the big rocks. Here the place with the tent. Did you cut enough willows for the lines, did you hang them, are they treble are they single, we’ll need the right hooks for the bait. We walked across water so cold here it was burning. It was warm. When you put your slippers on you have to watch your step, the grass is wet the tiles are wet it’s pitched a little down. So here hold the rod. When you don’t know where you are – 2. In Ptolemy’s Geometry the uncharted is not far away. Written in lampblack ink made from soot. Where is she. Never far beyond Serica beyond Sinae nothing the island of Taprobane then nothing and Aurea Cheronesus. Did you hear them first. Did you tie the boat to the willow to a stone. Inscribed on a roll of papyrus cut from plants growing along the Nile Delta. Why have you chosen Ptolemy do you think – 3. Harry T. Kelsh’s patents (1949–55) for the machine he sat at for a decade – my father working the arms, tracing contours with mechanical pencils onto semi-transparent paper – include photogrammetric plotting, gimbaled 1 6 Y diaphragms for optical projection, stereoscopic projection, compensator designs for moving the floating mark of the mapping table, instead of the lenses. Hence the Kelsh machine. He sat me down. To trace a path – 4. who could find his way in the woods in the dark in rainstorm and snow-cover when he fell the first time how did they know it he said he was disoriented who could tell which weed which root some manner of knot starlings in the blue crab kingfish or jay on a low branch of bobbing lindens where were you going but I don’t remember that who waited the last night quietly still through the long night and holding her hand – 5. I am seven or eight. He’s about thirty. Keep still now. Only cartography’s general reference map has the hubris to present the world, you know, as it really is, as if to say now and forever. Ground the heel to a stone, rock the rod to get your reading when the hash-mark’s high. Who carries me over water to our fire cicadas star-dots among weeping willows scent of the older herds. Any tree could be the axis mundi around which the universe turns – 1 7 R 6. Here I heard them singing. Marsh wrens. Her singing. Let’s chalk a path to the dining room. Let’s put a piece of tape on the drain on the floor to the north-point. This way we know where we are. His latitude expressed as climata, the length of the longest day, not degrees of arc. It’s where we stood. Furrows in a cornfield. What Ptolemy called chorography was simply a survey, it was not the world. He fell from a chair a ladder a tree – 7. It’s maybe four miles from East Circle to Adams Street Place. Place being where. Ptolemy’s purpose was not to imagine the whole of natural existence but account for the known edge, beyond which. He is eighty-eight. I am sixty. Beyond which we can’t see. The arms the pencils the 3-D stereo-glasses on a table stand. Limestone ledge there’s the back way down. Bring it up slow and check what we caught. Here hold on. I know where we’re going. She heard. I know. We won’t be back – ...

Reconstitution de l'entrée préhistorique de la grotte Chauvet-Pont d'Arc (Ardèche, France) : les apports de l'analyse géomorphologique et de la modélisation 3D

Reconstruction of the prehistoric entrance of the Chauvet Cave (Ardèche, France) : the contribution of geomorphologic analysis and 3d modelling. The exceptional state of conservation of the Chauvet Cave is mostly due to its sealing because of the collapse of the limestone ledge that used to overhang the prehistoric entrance. This article gives the very first synthesis of the works that have been carried out since 2005 on the entrance of the cave. Special attention is paid to the reconstruction and the chronology of the events that lead to the sealing of the cave. This reconstruction relies on a method coupling the geomorphologic approach and the 3D modelling with digital clones acquired by lasergrammetry. This original method allowed us to find the former extension of the Chauvet Cave that was cut off by the receding of the slope, to detail the features as well as the size of the prehistoric porch, and to assess the processes that occurred during the sealing of the cave. A relative chronology of the events is proposed in this article, in the present absence of dates able to constrain the morphogenetic model. After presenting the contribution of geomorphologic mapping to the understanding of the events that shaped the present relief, we elaborate on the contribution of 3D modelling to spatialise the geomorphologic data and better take into account the spatial and geometrical constraints. With this approach, we reveal the role of the ceiling pendants in the spreading of collapsed rocks within the cave and thus better grasp the structure of the internal scree ; likewise the identification of a gallery that was cut off allowed us to better understand the distribution of the collapsed rocks at the base of the scar and the small spatial extension of the internal scree. Finally, the analysis with high spatial resolution of the scar allowed us to estimate the volume of collapsed rocks and to measure their impact on the sealing of the cave. The age of the sealing is estimated with data today available from the dating of speleothems that seal up the scree and the underground fauna. The proposed bracket remains wide on the basis of these data : the cave was blocked off between 23 000 and 11 500 BP. In order to reduce this age bracket, we propose leads that could be followed to date the scar of the rockfall.

Influence of Benthic Features and Fishing Pressure on Size and Distribution of Three Exploited Reef Fishes from the Southeastern United States

AbstractDistribution, habitat preference, and size structure were examined for three commonly targeted bottom fishes (black sea bass Centropristis striata, gag Mycteroperca microlepis, and scamp M. phenax) in the southeastern United States. Fish communities and bottom characteristics of limestone ledges within Gray's Reef National Marine Sanctuary (located centrally along the southeastern continental shelf) were surveyed. Black sea bass occurred at 98% of the ledges and were evenly distributed throughout the sanctuary in much‐higher numbers than either gags or scamps, which were concentrated at only 11% of the ledges. Gag or scamp presence was most strongly related to height of ledge undercut, whereas abundance of black sea bass was best explained by percent cover of sessile biota. In addition, lower abundance of black sea bass occurred in the presence of either gags or scamps, which are generally larger than black sea bass. In all three species, an abrupt decline in abundance was observed for size‐classes above the size limit of the fishery. Also, modal size of gags or scamps was smaller and the percentage of fish exceeding the fishery size limit was lower in heavily fished areas than in less intensively fished areas.

John Graves, Writer (review)

2??8Book Reviews467 duction during the 1 950s and 1 960s. Then, after failures in Alaska and elsewhere, Shell returned to the Gulf in the 1980s and continued exploring and producing in even deeper areas of the Gulf. Priest becomes a storyteller as he explains that Shell led the way into "deep water . . . drilling, . . . production, . . . and subsea completions" (p. 99). The story carries the reader ahead with anecdotes about the Bay Marchand blowout and other stirring events. Finally, Priest artfully weaves Shell's successes and failures into an explanation of how Shell eventually disappeared as a distinct operating company. Despite die fact that this is an exciting narrative, several problems limited the book's effectiveness. Aldiough originally hired to write a sponsored narrative, Priest completed the book after Shell withdrew its support. However, the original project haunts the book as Priest introduces a multitude of Shell engineers, researchers, and managers to the reader. Priest also includes information diat is not germane to his argument, such as stories about the social upheavals of the 1970s and the dissolution of Shell Oil. Moreover, Priest assumes the reader has a great deal of knowledge about oil exploration and production. He fails to explain such terms as catalytic cracking tank, refraction seismography, heavy mud or "spud in"—terms familiar to chemists and geologists or oilmen but not usually familiar to the average historian. Many of the personal stories could have been edited out leading to a better flow offacts, and a glossary would have solved the second problem. However, some sections remain confusing because Priest provides few date queues while he moves back and forth continually tiirough thirty or forty years. Finally the book would have been enhanced with more diagrams and fewer pictures. Nevertheless, the book tells a dramatic story of imaginative businessmen and engineers who propelled Shell forward in the search for ways to locate and recover oil from the depths of the sea. Texas A&M UniversityKay Goldman John Graves, Writer. Edited by Mark Busby and Terrell Dixon. (Austin: University of Texas Press, 2007. Pp. 286. Illustrations, bibliography, index. ISBN 0-29271494 -7· $34-95. cloth.) John Graves is one of Texas's most celebrated writers, known for his literary skill and for his love of die Texas landscape. Sometimes called "The Sage of Glen Rose" (Texas), Graves first achieved critical acclaim for Goodbye to a River: A Narrative (i960), a memoir centered on a journey down the Brazos River before it was to be dammed. Goodbye has become a classic in environmental literature and was the first ofwhat was to become his "Brazos" trilogy that includes Hard Scrabble: Observations on a Patch ofLand (1974), and From a Limestone Ledge: Some Essays and Other Ruminations about Country Life in Texas (1980). In John Graves, Writer, editors Busby and Dixon have assembled the most comprehensive consideration of the life and works of Graves available, and their respect for die writer is evident in their selection and arrangement of material. Contributors to die volume share a connection to Texas or to Graves as residents 468Southwestern Historical QuarterlyApril of the state, longtime friends or students, teachers of environmental or Texas literature, or admirers. Following Busby's introduction to Graves, transcripts of a symposium and an interview with Graves at Texas State University in 2002 give the reader a personal sense of both man and work, providing a background for what others have to say about Graves. The next section contains essays written especially for this volume by friends of Graves, some of them fellow writers, each a tribute to man and author . The last and longest section is a collection of nine critical essays looking at style, theme, and technique in the works ofJohn Graves. These range from editor Dixon's essay situating Goodbye to a Riverwithin the tradition of environmental literature extending back to Thoreau to Cory Lock's consideration of Graves's long relationship widi Texas Monthly and the incongruity ofthe "fast-paced, progressive, urban" magazine publishing the "reflective, traditional, and rural" essays Graves contributed (p. 207). As a former English teacher, I was especially drawn to Dickie Maurice Heaberlin 's witty "Of Dachshunds and Dashes" which compares John Graves and E. B. White...

Exceptionally well preserved late Quaternary plant and vertebrate fossils from a blue hole on Abaco, The Bahamas

We report Quaternary vertebrate and plant fossils from Sawmill Sink, a "blue hole" (a water-filled sinkhole) on Great Abaco Island, The Bahamas. The fossils are well preserved because of deposition in anoxic salt water. Vertebrate fossils from peat on the talus cone are radiocarbon-dated from approximately 4,200 to 1,000 cal BP (Late Holocene). The peat produced skeletons of two extinct species (tortoise Chelonoidis undescribed sp. and Caracara Caracara creightoni) and two extant species no longer in The Bahamas (Cuban crocodile, Crocodylus rhombifer; and Cooper's or Gundlach's Hawk, Accipiter cooperii or Accipiter gundlachii). A different, inorganic bone deposit on a limestone ledge in Sawmill Sink is a Late Pleistocene owl roost that features lizards (one species), snakes (three species), birds (25 species), and bats (four species). The owl roost fauna includes Rallus undescribed sp. (extinct; the first Bahamian flightless rail) and four other locally extinct species of birds (Cooper's/Gundlach's Hawk, A. cooperii/gundlachii; flicker Colaptes sp.; Cave Swallow, Petrochelidon fulva; and Eastern Meadowlark, Sturnella magna) and mammals (Bahamian hutia, Geocapromys ingrahami; and a bat, Myotis sp.). The exquisitely preserved fossils from Sawmill Sink suggest a grassy pineland as the dominant plant community on Abaco in the Late Pleistocene, with a heavier component of coppice (tropical dry evergreen forest) in the Late Holocene. Important in its own right, this information also will help biologists and government planners to develop conservation programs in The Bahamas that consider long-term ecological and cultural processes.

Manipulation of environmental variables and the effect on the growth of Haliclona sp.: Implications for open-water aquaculture

We examined how the physical environment influences the growth and survival of an undescribed Haliclona species. To determine the influence that water movement, light and sediment had on the sponge, explants of Haliclona sp. (approximately 8 cm3 in size) were transplanted into manipulated microenvironments at Hamelin Bay on the west coast of Western Australia near Perth. The sponge is typically found under limestone ledges and appears to have distinct limits on the microenvironment in which it is found. A three-factor orthogonal design was used to manipulate levels of light, water flow and sedimentation. Each factor had two experimental levels, creating environments with high and low water movement, high and low light, and upward and downward orientations to control sediment levels. The survival of explants was high (100%). However, all explants showed a regression in weight. Explants transplanted on to the underside of horizontal surfaces (downward orientations) demonstrated significantly less weight loss (P = 0.023), which was attributed to lower sediment exposure. Light and water movement did not significantly influence the sponge's growth.

Embryogenesis and larval biology of the ahermatypic scleractinian Oculina varicosa

The ivory tree coral Oculina varicosa (Leseur, 1820) is an ahermatypic branching scleractinian that colonizes limestone ledges at depths of 6–100 m along the Atlantic coast of Florida. This paper describes the development of embryos and larvae from shallow-water O. varicosa, collected at 6–8 m depth in July 1999 off Fort Pierce, Florida (27°32.542 N; 79°58.732 W). The effect of temperature on embryogenesis, larval survival, and larval swimming speed were examined in the laboratory. Ontogenetic changes in geotaxis and phototaxis were also investigated. Embryos developed via spiral cleavage from small (100 µm), negatively buoyant eggs. Ciliated larvae developed after 6–9 h at 25°C. Embryogenesis ceased at 10°C, was inhibited at 17°C, and progressed normally at 25°C and 30°C. Larval survival, however, was high across the full range of experimental temperatures (11–31°C), although mortality increased in the warmest treatments (26°C and 31°C). Larval swimming speed was highest at 25°C, and lower at the temperature extremes (5°C and 35°C). An ontogenetic change in geotaxis was observed; newly ciliated larvae swam to the water surface and remained there for approximately 18 h, after which they swam briefly throughout the water column, then became demersal. Early larvae showed no response to light stimulation, but at 14 and 23 days larvae appeared to exhibit negatively phototactic behavior. Although low temperatures inhibited the development of O. varicosa embryos, the larvae survived temperature extremes for extended periods of time. Ontogenetic changes in larval behavior may ensure that competent larvae are close to the benthos to facilitate settlement. Previous experiments on survival, swimming speeds, and observations on behavior of O. varicosa larvae from deep-water adults indicate that there is no difference between larvae of the deep and shallow populations.

Athalamia hyalina (Sommerf.) S.Hatt. in Scotland, new to the British Isles

The liverwort Athalamia hyalina (Sommerf.) S.Hatt. and the family Cleveaceae are reported as new to the British Isles from the eastern Scottish Highlands. The Scottish plants are described and illustrated and the significance of the discovery is assessed. In Scotland, Athalamia hyalina occurs on thin soil on eroding limestone ledges in a montane habitat with a continental climate. It is in active growth in the winter months, producing spores in spring. Its range is restricted but it occurs within a protected area and is not threatened at present. The species is widespread in the northern hemisphere.

Grutter v. Bollinger/Gratz v. Bollinger: View from a Limestone Ledge

June 22, 2003 was a typically sultry summer day in Austin. The kids were swimming; white clouds with no promise of rain moved slowly across the sky. The sky itself was that bleached-out blue that it gets as summer starts to envelop the hill country and life seems to slow down to match the climate. I was sitting with one colleague watching our kids swim, and we were visiting with a former colleague who was in town connecting with old friends and shepherding his children around to see their friends. We were discussing the cases still pending before the Supreme Court and especially the Michigan cases. We had all listened to the oral arguments and had participated in the drafting of amicus briefs for this organization or that one. We each had our view about how the Court would decide

Silt Injection as a Mode of Fossilization: A Triassic Example

Near Salt Lake City, Utah, several limestone ledges in the upper part of the Thaynes Formation contain siltstone replicas of common Triassic pelecypods. Identical siliciclastic silt is abundant in the ledges in the form of narrow dikes, irregular seams, and thin beds. The casts formed when detrital silt filled molds created by dissolution of buried shells. A gravity-controlled process of mold filling is rejected because the casts are not concentrated beneath discontinuity surfaces, and individual specimens lack geopetal fabrics. By contrast, many casts are lateral extensions of dikes that die out upward in the host ledge, and many isolated, convex-up molds are completely filled from end to end, including the highest part of the arch. These features are evidence for injection of liquefied silt as the mold-filling process. The rarity of connections between dikes and thick, inter-ledge siltstone units indicates that layers and lenses of silt within the ledge-forming carbonates were the sources of the injected sediment. The availability of open molds as sites for injection indicates that the carbonate was at least partially lithified and subject to fracturing by the same event that mobilized the silt. The concurrent responses could have been triggered by rapid deposition of overlying strata, by passage of storm waves, or by an earthquake. Lack of sedimentologic evidence for either of the first two phenomena, plus the well-documented association of historical earthquakes with sediment liquefaction, leads to tentative acceptance of seismicity as the most likely of the three triggering mechanisms.

Abyssal erosion and scarp retreat: Deep Tow observations of the Blake Escarpment and Blake Spur

Deep Tow surveys conducted at two sites at the base of the Blake Spur and Blake Escarpment serve to delineate the contact between Mesozoic platform carbonates of the Blake Plateau and adjacent abyssal strata. The continental margin in the surveyed areas consists of steep limestone cliffs and headlands with over 2 km of relief. This extreme topography distorts the hydrographic structure of the water column and intensifies abyssal current flow in the surveyed areas. Significant lateral scarp retreat is indicated by the presence of broad, nearly horizontal benches of Mesozoic limestone presently exposed at the base of the Blake Spur and Escarpment in 4.5–5 km water depth; and by angular, apparently truncated limestone ledges that crop out on the cliff face. At the Blake Spur, the contact between Mesozoic platformal limestones and basinal Tertiary strata does not occur directly at the foot of the cliff, but is exposed on the abyssal plain within a 50 m deep erosional moat. Here, strong (>2 knots) south-flowing bottom currents occur within 100 m of the sea floor. The coincidence of this vigorous current flowing within the moat near the base of the escarpment and the eroded character of the sea floor suggests that currents are an important mechanism in sculpting this abyssal headland and contributing to lateral scarp retreat. Similar erosional processes are indicated along the Blake Escarpment near 29°03′N, where the relatively straight cliff face is interrupted by occasional steep-walled box canyons. On the headland between the canyons, the Mesozoic outcrop projects into the Blake–Bahama Basin for several kilometers as a broad, arcuate, gently-sloping bench. These outcropping benches of Mesozoic strata at the base of the escarpment are analogous to larger-scale buried benches observed in the subsurface that were formed by pre-Miocene erosion. Neogene and Quaternary scarp retreat is suggested by the location of the contact between Mesozoic rocks and younger strata seaward of the steeper cliff face, and is probably the result of current-induced erosion. Focused erosion may be facilitated by the presence of a thin (∼50 m) filament of corrosive Antarctic Bottom Water (AABW) that flows vigorously along the base of the cliff at both sites. The recessed position of the canyons shelters them from the main flow of this abyssal current, but the steepness and morphology of the canyon walls suggest that additional unidentified erosional processes are focused at the canyon heads.

From a Limestone Ledge by John Graves, and: The Desert Smells Like Rain by Gary Paul Nabhan

280 Western American Literature tablature. The songs that are presented are relayed line-by-line, in poem-form. Gone, too, are Danny Timmons’wonderful line drawings that accompanied the previous edition. The “Poetry”section (distinct from “Songs”) is expanded with nine new authors, while the “Fiction” section offers two additional—and three new—authors. Introductory essays precede each major section, and provide biographical sketches of authors. The collection remains rich and diverse in genre, source, and time. The pieces span the evolution of native American literature, from traditional to mainstream, from the ancient (though still active) oral tradition to selections from Scott Momaday and Louise Erdrich. As Velie admonishes, these works are not “quaint relics of a forgotten people”; rather, their common bond across traditions and regional cultures is their literary quality. D. E. McIVOR Utah Stale University From a Limestone Ledge. ByJohn Graves. (Louisville, Colorado: The Audio Press, 1990. 2 cassettes, 3 hours, $15.95.) The Desert Smells Like Rain. By Gary Paul Nabhan. (Louisville, Colorado: The Audio Press, 1990. 2 cassettes, 2'Y\ hours, $15.95.) Maybe it’s something atavistic in my character, but I like a good story, read aloud. And for those of us who regret the fading of the oral tradition from our culture, The Audio Press gives reason for hope. Gary Nabhan reads from two of his works: TheDesert Smells Like Rain (1982) and Gathering the Desert (1985). He is an ethnobotanist, and his tales, set in the Sonoran Desert, are of the intricately woven relationship between the Tohono O’odham (Papago), the land, and their domesticated, desert-adapted plants. John Graves is an astute observer of the ebb and flow of life on his Northcentral Texas farm. He reads from Hardscrabble (1973, 1974), and From a Limestone Ledge (1980). The stories speak of daily concerns, from choosing land to the management of a modest herd of cattle, to fencing, and working with the occasional Mexican immigrant. These avuncular stories are ultimately about John Graves, and I like that; they take me to his porch on a cooling Texas evening. D. E. McIVOR Utah State University World Outside the Window: The Selected Essays of Kenneth Rexroth. Edited by Bradford Morrow. (New York: New Directions, 1987. 319 pages, $12.95.) World Outside the Windoiu: The SelectedEssays ofKenneth Rexroth offers a broad swath of twenty-seven essays by the San Francisco poet, Asian-verse translator ...

Habitat Discrimination between Sympatric Populations of Peromyscus attwateri and Peromyscus pectoralis in West-Central Texas

Habitat discrimination between sympatric populations of Peromyscus attwateri and P. pectoralis was examined through live trapping, observations of escape cover, and fluorescent tracking. Discriminant-function analysis of live-trapping data defined the position of each species along a habitat gradient ranging from sloping limestone ledges with leaf litter under a live oak (Quercus fusiformis) canopy to more open grassy areas with scattered rocks and young mesquite (Prosopis glandulosa). P. attwateri was a generalist using the full range of available microhabitats. P. pectoralis specialized on areas of limestone ledges and leaf litter, and its microhabitat niche was included entirely within that of P. attwateri. Results of analysis of escape cover and fluorescent tracking for P. pectoralis confirmed the association of this species with limestone ledges. Both discriminant-function analysis and fluorescent tracking indicated that immature P. pectoralis used marginal habitats in addition to limestone ledges, therefore had a broader microhabitat niche than adults. Observation of escape cover and tracking revealed that on the study site, P. attwateri is at least semiarboreal and travels primarily in trees.

Determination of Some Trace Elements in Two Different Limestones by Atomic Absorption Flame Photometry

Perhaps the most monumental work on the analysis of eastern Kansas limestones, was done by Russel T. Runnels and co-workers (9). Their work and most other work, was done on composite samples (channel analysis). Until recently (6, 7) little or no work appears to have been done on the vertical variations in the chemical composition within a unit of limestone. The purpose of this study was to determine whether or not there is a difference in the vertical deposition of some trace elements in limestone in going from the bottom to the top of the bed. The elements studied to this time, are copper, chromium, nickel, vanadium, strontium, molybdenum and zinc. One of the two limestones studied was the Cottonwood Limestone bed, member of the Beattie Formation of the Permian System. This limestone bed consists of a ledge 5 to 7 feet thick and has at least three distinct layers. The top and bottom layer are approximately 3 feet in thickness and the center layer around 4 inches in thickness. The second limestone chosen for this work was the Burr Limestone, member of the Grenola Formation of the Permian System. This limestone ledge is also in three distinct layers with a total thickness of around 6 to 7 feet. The top and bottom layer are of approximately equal thickness of 3 feet. The center layer is about 1 foot in thickness and consists of shale, rather than limestone.

Chlorophyll Content of Deschampsia flexuosa Seedlings grown on a Calcareous and a Non-calcareous Soil

IT is well known that many plants characteristic of acid soils become chlorotic when grown on calcareous soils. This phenomenon is usually referred to as lime-induced chlorosis and has been associated with impeded iron metabolism of the plants grown on calcareous soils. This communication describes an unusual alteration in the ratio of chlorophyll a to chlorophyll b in plants showing chlorosis. Seedlings of Deschampsia flexuosa were grown on a mor soil collected from the surface, 5 cm beneath a Deschampsia flexuosa litter layer, and on a protorendzina soil collected from carboniferous limestone ledges where the soil depth seldom exceeded 5 cm. Both soils were sieved and placed in plastic pots. Seeds were germinated on moistened filter paper and seedlings planted one per pot. The plants were grown in a glass-house with additional illumination from Phillips ‘Daylight’ fluorescent tubes. The soils were moistened daily with glass-distilled water. Plants were harvested at intervals over a period of 6 weeks. Chlorophyll was estimated in an 80 per cent acetone extract of the fresh leaves from the optical densities at wave-lengths 645 and 663 mµ (ref. 1).

Les terrasses de la Garonne dans l'Agenais

Abstract In the Agen region, France, the evolution of the Garonne valley has been retarded by the presence of limestone ledges. The river terraces therefore are narrow and discontinuous, making observation and dating difficult. Detailed petrographic analysis of the terrace sediments has made it possible to distinguish a high terrace, whose deposits consist mainly of quartz pebbles, and three lower terraces with quartzite and granite constituents.

Additions to the Kansas Flora for 1956

Field and herbarium studies during the year have provided additional data concerning plants little known in the Kansas Flora or not recorded in previous publications. All specimens cited are in the herbarium at the University of Kansas unless otherwise indicated. Cheilanthes feei (Michx.) D. C. Eat. is a rare fern in Kansas and has been reported previously from Ottawa, Ellsworth, Hodgeman, and Ford counties. To this list may now be added Barber County on the basis of a specimen (Lathrop 2254). A collection from Chautauqua County (Lathrop 2338), crevices in limestone ledge, in a wooded gully, NW?4NE1/-S12-T33S-R10E, on May 20, 1956, is the first valid record for southeastern Kansas. A report from Woodson County is without specimen verification.

New Moss Records for Centre and Huntingdon Counties, Pennsylvania

floras of the central Pennsylvanian counties of Centre and Huntingdon, previously reported by Jennings (1951) and Moul (1952). list includes a total of 33 taxa, 21 for Centre and 12 for Huntingdon. Collections were made during August 1955 at ALAN SEEGER STATE FOREST MONUMENT, a hemlock-Rhododendron community in the northeastern part of Huntingdon County, BEAR MEADOWS STATE FOREST MONUMENT, a relic bog approximately eight miles southeast of State College, Centre County, and THE ROCK, a limestone ledge along Spring Creek about five miles northeast of State College, previously studied by Greenwood (1923) for hepatics and Thomson (1944) for lichens. All three localities lie within the Ridge and Valley Province. Specimens of the records are deposited in my personal herbarium, the Herbarium of the Florida State University, and, with a few exceptions, the Carnegie Museum, Pittsburgh. nomenclature follows, in the main, that of Grout (1940). following abbreviations are used in the list: AS: Alan Seeger State Forest Monument; BM: Bear Meadows State Forest Monument; R: The Rock.