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altered belt biotite Buckingham Byrd Creek calcite chiefly chlorite coal beds Coal Clay color contains copper country rock County crystals cyanite Daily gage height Day Jan deposits depth diameter Drainage dump east exposed feet feldspar fine-grained Fork formation garnets gneiss gold granite gravels gray Guests River gypsum hornblende hornblende schist igneous ilmenite inches inclusions iron James River June July Aug lenses limestone Location London and Virginia Macerady magnetite metamorphism microscope mill minerals mines northeast numerous occurs outcrops parallel partly pegmatite places plagioclase Pound River pre-Cambrian present probably production pyrite quadrangle quartz quartzite Richmond Roanoke rock Spec rutile Saltville sandstone schist schistosity second-feet sedimentary Sept sericite shaft shale short tons slate southeast southwest specimen square miles strike surface Tellurium thick thin section vein quartz veinlets vicinity wall rock Willis Mountain yards zircon
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Seite 1 - Maximum" gives the mean flow, us determined from the rating table, for the day when the mean gage height was highest. As the gage height is the mean for the day, it does not indicate correctly the stage when...
Seite 86 - ... Hornblende Gabbro. Road between Pelmadulla and Haldummulla, mile post 76 A rock, somewhat similar to that just described, is here opened up in another quarry which lies further to the southeast. The rock is dark in color and on the fresh fractured surface shows minute red garnets disseminated through it. Under the microscope the rock is seen to be composed of plagioclase, diopside, hypersthene, hornblende with red garnet as essential constituents, but contains no orthoclase, quartz or iron ore....
Seite 131 - How was retarded by freezing; reported that practically no water was flowing. Winter flow. — Ice seldom forms at station, but flow is sometimes retarded by freezing of headwaters. Accuracy. — Frequent measurements necessary to adequately define rating curve at low stages. Rating curves at high stages not well defined, and estimates of discharge only fair except for periods during which frequent measurements were made.
Seite 2 - ... and knowledge of local conditions. In this column A indicates that the mean monthly flow is probably accurate within 5 per cent; B, within 10 per cent; C, within 15 per cent; D, within 25 per cent.
Seite 49 - ... material very similar in character to that of the quartz epi-diorite in the area east of Berkley. Megascopically this rock is grayish-green with phenocrysts of clear, glassy quartz grains as large as a quarter of an inch in diameter. The groundmass is green with a decidedly laminated appearance. Under the microscope the rock is seen to be composed of quartz, saussurite, chlorite, hornblende, biotite, pyroxene, and pyrite. Quartz usually occurs as a mosaic aggregate, although single large grains...
Seite 1 - ACCURACY OF FIELD DATA AND COMPUTED RESULTS The accuracy of streamflow data depends primarily on (1) the stability of the stage-discharge relation or, if the control is unstable, the frequency of discharge measurements, and (2) the accuracy of observations of stage, measurements of discharge, and interpretation of records. The station description...
Seite 1 - In the table of monthly discharge the column headed "Maximum" gives the mean flow, for the day when the mean gage height was highest. As the gage height is the mean for the day it does not indicate correctly the stage when the water surface was at crest height and the corresponding discharge was consequently larger than given in the maximum column. Likewise in the column headed "Minimum" the quantity given is the mean flow for the day when the mean gage height was lowest.
Seite 1 - ... data. In order to give engineers and others information regarding the probable accuracy of the computed results, footnotes are added to the...