Frederick M. Swain

Limnology and Amino-Acid Content of Some Lake Deposits in Minnesota, Montana, Nevada, and Louisiana

Sedimentary features and amino-acid content are described for several lakes in the Anoka sand plain, east-central Minnesota, other lakes in Minnesota, Flathead Lake, Montana, Pyramid Lake, Nevada, and Catahoula Lake, Louisiana. The limnology of the Anoka Sand Plain lakes is related to the characteristics of the “gray” sandy calcareous Mankato drift of the Des Moines lobe which underlies much of the sand plain; the “red,” less calcareous, Superior lobe drift which forms the eastern border of, and patches within, the sand plain has less effect on the lakes. The scarcity of varved Recent lake deposits in Minnesota is believed to result in large part from the reworking activity of benthonic organisms. As a result, measurements of some properties of the mixed bottom materials have little chronologic significance. Free amino acids are rare or absent in the lake sediments, but amino acids ranging from less than 2 ppm to more than 4000 ppm on a wet-weight basis were obtained in acid hydrolysates of the sediments. The amino acids probably occur as glutelin or scleroprotein types of proteins, as peptides, or tied to humic-acid substances in these sediments. Neutral peat deposits and well-humified organic lake deposits yield neutral and acidic amino acids in approximate proportions of 6:1; alkaline bogs and well-humified organic marls yield neutral and acidic amino acids in proportions of about 3:1; acid peats contain basic amino acids in addition to neutral and acidic types. Incompletely humified lake deposits yield variable proportions of all three types of amino acids. To the extent that the amino acids were involved in microbiological transformations in the accumulating deposits, the observed proportions of the ammo acids are believed to be related to their Zwitter ion properties. Lake sediments of low organic content generally yield small amounts of neutral amino acids but typically lack acidic or basic ammo acids.

Carbohydrates from Precambrian and Cambrian Rocks and Fossils

Carbohydrate residues in eleven samples of early to late Precambrian rocks and fossils and one sample of Middle Cambrian Burgess Shale ranged from traces to more than 5 μg/g Free monosaccharides and a disaccharide, acid-extractable (polymeric) sugars, and recognizable polysaccharides were found in the samples. Geological conditions in the sampling areas suggest that the free sugars, being water-soluble, may not be indigenous to the rock but perhaps were introduced by ground-water circulation during the present or a preceding erosion cycle. Available evidence suggests that the acid-extractable monosaccharides and polysaccharides are at least partly native to the rocks or fossils in which they occur. The acid-extractable sugars obtained in these samples are β-D-galactose, β-D-glucose, mannose, arabinose, xylose, ribose, and rhamnose; the first two were identified enzymatically and they and the other sugars were also identified chromatographically. The polysaccharides found in these samples are linear α —1 →4 glucopyranose units suggesting starch, β — 1 → 4 glucopyranose units suggesting cellulose, and β — 1 → 3 glucopyranose unitssug-gesting laminaran. No starch residues were found n i the two lower Precambrian samples (Soudan and Coutchiching), but a trace of celluloseand laminaran was obtained in the Coutchiching. This may be an indication that cellulose-type structural polysac-charides and laminaran-type reserve sugars, but not starch-type food-reserve polysaccharides, existed in the early Precambrian.

Ostracodes of the Middle Devonian Onondaga beds of central Pennsylvania

Collections from the Middle Devonian Onondaga shale and limestone of central Pennsylvania and northeastern West Virginia have provided an abundance of Ostracoda, and the field work has also yielded much information concerning the lithologic features and the relationships of the Onondaga deposits. Descriptions are given of the Onondaga beds observed at 12 localities in Pennsylvania and 2 in West Virginia, and the stratigraphy as seen at these places is discussed. A total of 40 ostracode species has been recognized in the area. Of these, 3 were previously described, 35 are new. and 2 are represented by material too poor for specific description. The species are distributed through 11 families and 22 genera, 3 of the latter being new. For comparisons with members of this fauna, new figures and descriptions are given of 3 species from the Jeffersonville limestone of Kentucky, and of 1 from the Hamilton shale of Ontario. Four ostracode zones are recognized in the Onondaga beds near New Bloomfield, Pennsylvania. One of these is widespread; further work is needed to indicate the geographic distribution of the other three. The assemblage as a whole is not close to the known ostracodes of the Onondaga of New York, but further study of the latter will be needed before trustworthy conclusions can be drawn. The ostracodes of the Onondaga of Pennsylvania are clearly distinct from those of the Jeffersonville limestone of Kentucky, suggesting an appreciable difference in age. There are important affinities with ostracodes of the Camden chert of western Tennessee as recently studied by Bassler, but the latter assemblage includes numerous Oriskany elements and is clearly older.

Carbohydrate components of Paleozoic plants.

The residual monosaccharide components in aqueous and acid extracts of 25 species of Devonian-Permian plant fossils range from traces to 420 micrograms per gram. The species are distributed as follows: Pteridophyta-Psilophytales (2 species), Pteriodophyta-Equisetales (4 species), Pteridophyta-Lycopodiales (9 species), Pteridospermatophyta (6 species), Gymnospermae-Cordaitales (4 species).