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Norman F. Sohl

Publications and source records attributed to Norman F. Sohl.

9 recordsLinked to original sources
USGS2015

On the distribution of species occurrence

The distribution of species abundance (number of individuals per species) is well documented. The distribution of species occurrence (number of localities per species), however, has received little attention. This study investigates the distribution of species occurrence for five large data sets. For modern benthic foraminifera, species occurrence is examined from the Atlantic continental margin of North America, where 875 species were recorded 10,017 times at 542 localities, the Gulf of Mexico, where 848 species were recorded 18,007 times at 426 localities, and the Caribbean, where 1149 species were recorded 6684 times at 268 localities. For Late Cretaceous molluscs, species occurrence is examined from the Gulf Coast where 716 species were recorded 6236 times at 166 localities and a subset of this data consisting of 643 species recorded 3851 times at 86 localities. Logseries and lognormal distributions were fitted to these data sets. In most instances the logseries best predicts the distribution of species occurrence. The lognormal, however, also fits the data fairly well, and, in one instance, better. The use of these distributions allows the prediction of the number of species occurring once, twice, …, n times. Species abundance data are also available for the molluscan data sets. They indicate that the most abundant species (greatest number of individuals) usually occur most frequently. In all data sets approximately half the species occur four or less times. The probability of noting the presence of rarely occurring species is small, and, consequently, such species must be used with extreme caution in studies requiring knowledge of the distribution of species in space and time.

Paleobiology↗
USGS1973

Glauconites from New Jersey-Maryland coastal plain: Their K-Ar ages and application in stratigraphic studies

Glauconite samples from various stratigraphic levels in the northern Atlantic Coastal Plain were dated by the K-Ar method. Twenty-eight samples were collected from glauconite-bearing sands in four traverses across the outcrop belt of Upper Cretaceous–lower Tertiary formations from northern New Jersey to eastern Maryland, thus providing a framework on which to test the reliability of glauconite for dating in vertical sequences and within some formations along strike. Sample ages were determined paleontologically and radiogenically. The results show that most radiogenic determinations of glauconite followed a systematic pattern; the resultant ages were generally younger upward through the Stratigraphic section. In addition, consistent ages were obtained from many of the stratigraphic units along strike. A combination of paleontologically derived ages and the numerical radiogenic ages suggests that the stages of the Late Cretaceous are unequal rather than equal as some have proposed. For example, Campanian and Paleocene times are of significantly greater duration than the Maestrichtian. Several samples obtained across the Cretaceous-Tertiary boundary indicate that the age of the boundary is between 63.2 and 59.1 m.y., probably very near 61.1 m.y. Dates considered to be reliable were obtained from 25 of 28 samples. Two of the three discordant ages are ascribed to incomplete glauconitization of the pre-existing mineral phase and hence to mineral impurity. No adequate explanation for the third significantly younger age has been determined.

Delaware, Maryland, New Jersey, Pennsylvania↗
USGS1969

The fossil record of shell boring by snails

The predatory boring habit common to many recent snails probably arose first in the Polinicinae (Naticacea) during Upper Cretaceous (Cenomanian) times (100 million years B.P.) . In the fossil record the frequency of bored shells increases greatly in rocks of latest Cretaceous age and becomes more widespread during early Tertiary times coincident with the major diversification of the primary groups of boring snails. The borings in these Cretaceous and Tertiary shells show the same characteristics of preference of penetration in one pelecypod valve rather than the other or in position of the boring site on the shell that are found in recent shell assemblages. Borings in Paleozoic brachiopod shells (230–550 million years old) that have previously been attributed to gastropod predation are herein attributed to other but unknown boring organisms. In part these borings are not accepted as evidence of Paleozoic gastropod predation because it necessitates: (1) Postulation of the separate development of a boring habit with its concomitant development of an accessory boring organ in a group whose descendants are all herbivores, and (2) The development of such a habit hundreds of millions of years before the appearance of any relatives of present day borers.

American Zoologist↗
USGS1964

Studies of pre-Selma Cretaceous core samples from the outcrop area in western Alabama

In 1954 four core holes were drilled in the pre-Selma Cretaceous strata of the Alabama Coastal Plain in order to get unweathered samples within a few miles of the outcrops. During the next few years several specialists studied the cores, and their reports are published as consecutive parts of this bulletin. Watson H. Monroe, who spent many years studying the Coastal Plain strata in Alabama and Mississippi, conceived and supervised the drilling and planned the later studies. His earlier published report (W. H. Monroe, 1955, Cores of pre-Selma Cretaceous rocks in the outcrop area in western Alabama: Gulf Coast Geol. Societies Trans., v. 5, p. 11-37) contains a brief description of the stratigraphy, together with logs and other information regarding the core holes, and he has provided the introductory chapter to this bulletin. Richard E. Bergenback studied the petrology of the cores, which included finding the distribution of grain sizes, determining the mineralogy of the grains and the matrix of the sediments, and having X-Ray identifications made of the clay minerals. Norman F. Sohl studied the mollusks and other large fossils obtained from the cores and compared them with other faunal suites collected in Alaban1a and Texas. Esther R. Applin studied the sparse microfauna, comparing it with faunas obtained from deep wells downdip in Georgia, Alabama, and Mississippi and with outcrop samples fron1 Texas, and has described a new species of Foraminifera. Estella B. Leopold and Helen M. Pakiser obtained a large pollen and spore assemblage by digesting carbonaceous layers of some of the cores in acid; this flora includes much new material, which is not described here. The Bergenback, Sohl, and Applin reports discuss the probable environment in which the sediments accumulated. Louis C. Conant, who spent several years studying and mapping these sediments, has written a summary chapter integrating some of the surface and subsurface information. Quarter-cuts of the cores belonging to the U.S. National Museum have been deposited on indefinite loan with the Alabama Geological Survey at University, Ala., and with the Shell Oil Co. at Jackson, Miss. They are available there for inspection and study.

Bulletin↗
USGS1964

Giant Upper Cretaceous oysters from the Gulf coast and Caribbean

Two unusually massive ostreid species, representing the largest and youngest Mesozoic members of their respective lineages, occur in Upper Cretaceous sediment of the gulf coast and Caribbean areas. Their characteristics and significance, as well as the morphologic terminology of ostreids in general, are discussed. Crassostrea cusseta Sohl and Kauffman n. sp. is the largest known ostreid from Mesozoic rocks of North America; it occurs sporadically in the Cusseta Sand and rarely in the Blufftown Formation of the Chattahoochee River region in Georgia and Alabama. It is especially notable in that it lacks a detectable posterior adductor muscle scar on large adult shells. C. cusseta is the terminal Cretaceous member of the C. soleniscus lineage in gulf coast sediments; the lineage continues, however, with little basic modification, throughout the Cenozoic, being represented in the Eocene by C. gigantissima (Finch) and probably, in modern times, by C. virginica (Gmelin). The C. soleniscus lineage is the first typically modern crassostreid group recognized in the Mesozoic. Arctostrea aguilerae (Böse) occurs in Late Campanian and Early Maestrichtian sediments of Alabama, Mississippi, Texas(?), Mexico, and Cuba. The mature shell of this species is larger and more massive than that of any other known arctostreid. Arctostrea is well represented throughout the Upper Jurassic and Cretaceous of Europe, but in North America, despite the great numbers and diversity of Cretaceous oysters, only A. aguilerae and the Albian form A. carinata are known. The presence of A. aquilerae in both the Caribbean and gulf coast faunas is exceptional, as the Late Cretaceous faunas of these provinces are generally distinct and originated in different faunal realms.

Professional Paper↗