A PCTROGRAPHIC COMPARISON OF THE LOWER SPRABERRY mO THE DE4N SI LISTONES OF THE NORTHERN MIOÜ^D BASIN DE MEST TEXAS

A THESIS IN GE0L06Y BY

CHARLES ODELL TUCKCR

APPROVED

ACCEPTED

TEXAS TECHMOLOGICAL COLLEGE

AUGUST, L955 A PETROGRAPHIC COMPARISON OF THE LOMER SPRABERRY AND THE DEAN SI LISTONES OF THE NORTHEPN MIDUV4D BASIN OF WEST TEXAS

A THESIS IN GEOLOGY

SUBMITTEO TO THE GRADÚATE FACULTV OF TEXAS IccHNOLoaiCAt COLLEGE IN PARTÍAL FULFILLMENT or THE REQUIREMENTS FOR THE OEGREE OF

MASIER OF SCIENCE

BY

CHARLES OOELL IUCKER, B. S.

PETERSBURGf IEXAS

AUGUST, 1955 /y<<'-

lABLE OF CONIENIS

CHl\PTER PAGE

I INIROOUCIION 1

PURPOSE OF THE STUOY 1 ÁREA COVEREO 1 LOCATION MAP 2 pREVious WORKS 3 METHODS USED 4 II LIIHOLOSY 6 til PEIROGRAPHY 10

LOWER SPRABERRY 10 DEAR 13 PETROGRAPHIC COMPARISONS 15 IV CONaUSIONS. 17

REFERENCES CITED 18

APPENDIX 27 IHIN-SECTION DESCRIPTIONS 27 CROSS SECTIONS 75 LIST OF FIGURES

FIGURE P>GE

1 LOWER SPRABERRY LAMIÑATEO SlLTSTONE (X 36) CROSSEO NICOLS 7

2 DEAN LAMÍ ÑATEO SILTSTONE (X 36) CROSSED NICOLS 7

3 SAME AS FIGURE I NICOLS NOT CROSSED 7

4 SAME AS FIGURE 2 NICOLS NOT CROSSED 7

5 LOWER SPRABERRY MASSIVE SlLTSTONE (X 36) CROSSEO NICOLS 9

6 DEAN IHUSSIVE SILTSTONE (X 36) CROSSED NICOLS 9

7 SAME AS FIGURE 5 NICOLS NOT CROSSED 9

8 SAME AS FIGURE 6 NICOLS NOT CROSSED 9 AOCNOWLEDGEMerfrS

THE WRITER ACKNOWLEOGES WITH GRATITUDE HIS INDEBTEDNESS TO THE MEMBERS OF

Hlf AOVIfORY COMMITTEE, OTHER MEMBERS OF THE FACULTY OF IEXAS IECHNOLOGICAL COLLEGE,

ANO TO ICXAS IECHNOLOGICAL COLLEGE FOR USE OF LABORATORY FACILITIES.

IHC WfllTER WISHES TO THANK THE STANDARD OlL COMPANY OF IEXAS AND THE STAFF OF THEIR LUBBOCK DlSTRICT FOR THEIR FULL COOPERATION IN PEIMITTING HIM USE OF THEIR WELL LOGS, CORES» SAMPLES. LABORATORY MATERIALS, AND LABORATORY FACILITIES.

THE WRITER IS ALSO INOEBTED TO HIS PARENTSt MR. AND MRS. L. 0. lUCKCR, AND TO HIS wiFE, COLEEN, WITHOUT WHOSE AID AND ENCOURAGEMENT THIS THESIS «VOULD NOT HAVE

BEEN POSSIBLE. ABSIRAa

THE PURPOSE OF THIS STUOY WAS TO DETERMINE WHETHER A DISTINCTION COULD

BE MADE BETWEEN THE LOWER SpRABERRY AND THE DEAN SILTSTONES BY MEANS OF A PETRO­

GRAPHIC STUOY. THIN-SECTIONS WERE HADE AND STUOIED WITH THE RESULTING CONCLUSIONS:

NO DISTINCTION CAN BE MADE BETWEEN THE TWO SILTSTONES BY THIS METHOO; THERE ARE

INOICATIONS OF A COMMON 90URCE; THERE ARE INDICATIONS OF SIMILAR CONOITIONS

EXISTING PRIOR, DURING, AND AFTER OEPOSITION OF THE TWO SILTSTONES. IHE WRITER

PROPOSES THAT THE TERM "SPRABERRY FORMATION" BE ENLAR6ED TO INCLUDE TNE DEAN AS A

LOWER MEMBER. THE SPRABERRY FORMATION WOULD THEN REPRESENT A COMPLETE LITHOLOGIC

UNIT. A DETAILED LITHOLOGIC OESCRIPTION OF THE DEAN SlLTSTONE IS PRESENTEO. IHE

WRITER CONCLUDES THAT AN X-RAY ANALYSIS STUOY OF THE CLAY MINERALS MIGHT PROVIDE A

MORE DEFINÍTE METHOO FOR CORRELATIONS OF THE TWO SILTSTONES. CHAPIER I

INIROOUCIION

THIS STUOY ARISES FROM THE FACT THAT STAFF GEOLOGISTS OF THE LUBBOCK

DlSTRICT OF THE STANDARD OlL COMPANY OF IEXAS FOUND THE ACCURACY OF ELECTRIC LOGS

QUESTIONABLE FOR PICKING DEAN TOPS IN ÁREAS OVER THE PERMO-fENNSYLVANIAN REEF "HIGHS" OF DAWSON, GAINES, TERRY ANO LYNN COUNTIES. THE SPRABERRY AND DEAN SILT^ STONES DEFY LITHOLOGIC DIFFERENTIATION BY ORDINARY MICROSCOPIC EXAMINATION.

ALTHOUGH ELECTRIC LOGS ARE SUCCESSFUL FOR OORRELATION OF THE SpRABERRY AND DEAN

TOPS IN FOREREEF AND BACKREEF ÁREAS, THEY SHOW NO DEFINÍ TE BREAKS SEPARATING THE

LOWER SpRABERRY AND THE DEAN ABOYE THE REEF ÁREAS. USABLE PALEONTOLOGICAL DATA ARE VERY RARE IN THIS ÁREA. WOLFCAMP FUSILINIDS ARE REPORTED TO HAVE BEEN FOUND

IN THE LIMESTONE BETWEEN THE SPRABERRY AND DEAN SANOSTONES ANO UNDERLYING THE DEAN

IN SEVERAL WELLS (MCLENNAN AND BRAOLEY, 1951, P. 907).

THE PURPOSE OF THIS STUOY WAS TO DETERMINE WHETHER A DISTINCTION COULD

BE MADE BETWEEN THE LOWER SPRABERRY SlLTSTONE AND THE OEAN SlLTSTONE BY MEANS OF A

PETROGRAPHIC STUOY OF THIN-SECTIONS OF THE TWO SILTSTONES.

THE ÁREA COVEREO IN THIS STUOY INCLUOES NORTHEASTERN GAINES, NORTHWESTERN

DAWSON, SOUTHEASTERN TERRY AND SOUTHWESTERN LYNN COUNTIES, TEXAS. THIN«*SECTIONS

MADE FROM SAMPLES FROM ELEVEN WELLS IN THIS ÁREA WERE STUOIED. ELECTRIC LOGS FROM

THESE AND OTHER WELLS IN THIS ÁREA WERE ALSO CAREFULLY EXAMINED. k FUL TON CITIES PROD EUBANK TERRY ST ARNÉS A LYNN

TURNER DURH AM­ BO HA NON AMERADA WILSHIRE ^ILLARD HUMBLE BELL-^ CITIES SERV /O GREGORY

y y y y^

DELHI OlL ^EV O .MONCRIEF A /N SCANLAN 1-89 CITIES SERV LEVERETT l-B / y \ O STANOLIND \ I X AM WRHSE : y / US SMEL TING X ^SANDIDGE y ,/ o y / TEXAS CRUDE / ALSABROOK CLASSEN 2-95 "cARAWA, DUNhf.^ sLOE o O B y / / y

SINCLAIR ^ I GAINES y O / DAWSOÑ ^y LAMESA SEA BOARD ^ DOSS y oy

>^ALL a STEWART ^LATTENfíoFF o"

y / /

y y / FOREST a PR, o 16, 000 "1 C PARKER CO O 32,00 0 SCALE IN FEET

C.o.r ••h-i.: PREVIOUS IWJRKS

CONSIDERABLE WORK HAS BEEN PUBLISHEO ON THE SPRABERRY FORMATION BUT ONLY

ONE PUBLICATIÓN, MCLENNAN ANO BRAOLEY (1951) HAS PRESENTEO ANY SPECIFIC INFORMATION

ON THE DEAN EXCEPT IN REFERENCE TO ITS STRATIGRAPHIC POSITION BELOW THE SpRABERRY. MCLENNAN AND BRAOLEY (1951) NAMED, DESCRIBCD. AND QAVE TYPE LOCALITIES

FOR BOTH THE SPRABERRY AND THE DEAN SANDSTONES. FOR THE SpRABERRY TYPE SUBSURFACE

SeCTION THEY SUBMITTEO THE SANDSTONE SECTION OCCURRINQ BETWEEN 6,400 AND 7,290 FEET

IN SCABOARD'S SPRABERRY NO. 6-0, SEC. 38, BLOCK 34, I. 5 N., IN THE SpRABERRY FÍELO

OF EASTERN DAWSON COUNTY- THEY STATED THAT SEABOARO GEOLOGISTS FIRST APPLIED THE

ÑAME "DEAN SANDSTONE" TO THE SANDSTONE SECTION FROM 7,990 TO 8.190 FEET OF GULF OIL

CoRpORATiON's DEAN NO. L, SEC. 30. BLOCK 1, J. PORTEVANT SURVEY, DAWSON COUNTY,

TEXAS, 19 MILES NORTH OF THE SPRABERRY FÍELO. THE SPRABERRY TYPE SUBSURFACE SECTION

IS OESCRIBED FROM CORES WHILE THE DEAN TYPE SUBSURFACE SECTION IS DESCRIBED FROM

ROTARY CUTTINGS. IN GENERAL, THE SPRABERRY IS CONSIOERED AS LOWER LEOHARO ANO THE

DEAN AS THE UPPER WOLFCAMP IN AGE.

ARTICLES CONTAINING PETROGRAPHIC INFORMATION ON THE SpRAKRRY ARE:

SCIMITT (1954), WARN AND SIDWELL (1953) ANOGlBSON (1951). IK^ITERS WHO HAVE MENTION-

EO THE LITHOLOGIC SIMILARITY BETWEEN THE SpRABERRY ANO THE OEAN SANDSTONES ARE:

ANOERSON (1953, p. 512), MCLENNAN AND BRAOLEY (1951, p. 904) AND WARN, CARMACK AND

SlOWELL (1952, P. 114). BARTLEY (1951, P. 101) ANOGlBSON (1951, P. 107) DESCRIBED

THE SPRABERRY AS A TRUE SILTSTONE RATHER THAN A SANDSTONE. SINCE BOTH THE SPRABERRY

ANO THE DEAN "SAMDS^ ARE PREDOMINANTLY OF SILT SIZE IN THE ÁREAS UNOER CONSIOERATION

WITHIN THIS PAPER, THEY WILL BE REFERRED TO AS SILTSTONES.

THE WRITER'S STUOY OF THE «PPER SPRABERRY REVEALEO IT TO BE LITHOLOGICALLY

SIMILAR TO THE LOWER SPRABERRY, AS WAS STATED BY ANOERSON (1953, P. 512) ANO

MCLENNAN ANO BRAOLEY (1951, p. 904). THIS PAPER WILL BE CONCERNEO WITH THE LOWER

SPRABERRY SILTSTONE ANO THE DEAN SILTSTONE WITH THEIR OIFFERENTIATION AS THE

OBJECTIVE. IN APPROACHING THE PROBLCM THE WRITER FIRST STUOIED KNOWN SECTIONS OF

THE UPPER AND LOWER SPRABERRY IN THE FOREREEF OR BASIN FACÍ ES FOR THE ÁREA UNOER

CONSIOERATION. NEXT, THE WRITER STUOIED THE BACKREEF SECTION ANO, LAST, THE

QUESTIONABLE REEF ÁREA.

ALL THIN-SECTIONS USED WERE PRCPARED BY THE WRITER. IHE ONLY CORES

AVAILABLE WERE FROM THE UNITED STATES SMELTING ANO REFINING COMPANY NO. 1 SANDIOGE.

FOR INTERVALS NOT COVEREO BY THE CORES IN THIS WELL, ROTARY CUTTINGS WERE THIN-

SECTIONEO. A MODIFICATION OF THE THIN^ECTION PROCEOURE FOR CARBONATES USED BY THE

STANDARD OIL COMPANY OF TEXAS WAS EMPLOYEO. THE SILTSTONE CHIPS, USUALLY FIVE TEN*

FOOT INTERVALS, WERE PICKEO FROM THE ROTARY CUTTINGS AND FIRST MOUNTEO WITH LAKESIDE

NO. 70. THC REFRACTIVE INOEX OF LAKESIDE NO. 70 WAS DETERMINEO AND FOUND TO BE

1.54 OR THE SAME AS THAT OF CANAOA BkLSAM. LAKESIDE NO. 70 WAS FOUND TO BE

SUPERIOR TO CAÑADA BALSAM AS AN AOHESIVE. AFTER THE FIRST MOUNTING, THE CNIPS WERE

GROUND ON A LAP USINQ NO. 600 CARBORUNDUM POWOER. IHE CNIPS WERE THEN TURNEO OVER

ANO GROUNO OOWN AGAlN ON THE LAP. EXPERIMENTS WITH DIFFERENT ABRASIVES FROM NO.

150 TO No. 1000 MESH CARBORUNDUM POWDER WERE MADE ANO NO. 600 CARBORUNDUM POWDER

WAS FOUND TO BE THE MOST SUCCESSFUL FOR BOTH THE INITlAL ANO FINAL POLISHINQ ON A

LAP. AFTER THE FINAL POLISHING, THE SLIDES WERE SPRAYEO WITH "KRYLON," A CLEAR

ACRYLIC PLÁSTIC SPRAY WHICH ORÍES IN 5 TO 10 MINUTES. ANY NUMBER OF SLIDES CAN BE

SPRAYEO AT ONE TIME. THE REFRACTIVE INOEX OF THE SPRAY WAS DETERMINEO AND FOÜMD TO

BE 1.488 AS COMPAREO TO 1.51 FOR ORDINARY COVER GLASSES. THE EFFECT OF THIS

OIFFERENCE IN REFRACTIVE ÍNDICES ON THE REFRACTIVE ÍNDICES OF THE VARIOUS MINERALS

STUOIED IN THESE THIN-SECTIONS WAS NEGLIGIBLE. INE TECHNIQUE WAS CHANGED ONLY

SLI6HTLY TO MAKE THE THIN*SECTIONS FROM THE «ORES. NEAR-VERT I CAL FRAGMENTS WERE

BftOKEN FROM THE CORE CHIPS, HELO BY HAND FOR THE FIRST GRINDINS; THEN MOUNTEO ANO

FINISHED ON THE LAP AS WERE THE OTHER THIN-SECTIONS.

THE THIN-SECTIONS WERE STUOIED UNOER A PETROGRAPHIC MICROSCOPE USINQ A lOX EYEPIECE ANO A lOX OBJECTIVE LENS FOR GENERAL STUOY AND A 19X EYEPIECE AND A

43X OBJECTIVE LENS FOR OETAlLED STUOY FOR DETERMINING ORDER OF INTERFERENCE COLORS, 4 INTERFERENCE FIGURES, ANO OTHER PERTINENT INFORMATION.

IWO DIMENSIONAL SPHERICITIES WERE DETERMINEO BY PROJECTING THE SLIDES AND 5

COMPARING THE GRAINS WITH THE "CHART FOR ESTIMATING TWO^IMENSIONAL SPHERICITY" OF

RlTTENHOUSE (1943, PP. 79-61).

A LEITZ 1 M.M. SCALE WAS PROJECTED ANO A CHART t>RAWN FROM THE PROJECTION

FOR USE IN COUNTING AND MEASURING GRAINS. IHE SLIDES WERE PROJECTED ON THE CHART

WITH THE PROJECTOR IN THE SAME LOCATION FOR GRAINS SI2E AND COUNT. ÍHE AOCURACY

WAS CHECKED BY PERIOOICALLY PROJECTING THE 1 M.M. SCALE SLIDE ON THE CHART TO CHECK

AGAINST ANY CHANGE IN THE POSITION OF THE PROJECTOR. MEASUREMENTS WERE CHECKED

LATER BY USING AN OCULAR MICROMETER.

HEAVY MINERAL ANALYSIS WAS ATTEMPTED BUT THE CEMENTING MATERIAL FAILED

TO BREAK OOWN. CORE SAMPLES OF 25 GRAMS EACH WERE TAKEN FROM BOTH THE LOWER

bPRABERRY AND THE DEAN. A SAMPLE FROM EACH WAS PULVERIZEO WITH A MORTAR ANO PESTLE.

BOILEO IN 18)( HCL FOR 30 MINUTES, ORIEO, SIEVED, AND FOUNO TO YIELD AOGREGATES IN

THE 200-MESH SIEVE. IWO SETS OF SAMPLES WERE PUT IN 18^ HCL WITH STANNOUS CHLORIDE

TO FORM A 10| SOLUTION ANO BOILED FOR 30 MINUTES. IHIS ALSO YIELOED AGGREGATES IN

THE 200-MESH SIEVE. IwO OTHER SAMPLES WERE BOILED IN A 7^ SOLUTION OF AMMONIUM

HYDROXIDE, BUT THIS PROCESS FAlLEO TO FREE THE GRAINS. A THIRD SET OF SAMPLES WAS

THEN BOILED IN A 14^ SOLUTION OF AMMONIUM HYDROXIDE FOR 30 MINUTES WITH THE SAME

RESULTS. THE USE OF BROMOFORM ON THESE SAMPLES AFTER BOILING, DRYING, AND SIEVING,

FAlLEO TO PRODUCE ANY SEPARATION. KNOPF (1933) USED HYDROFLUOSILICIC ACIO IN

OETERMININQ THE *FREE SILICA" IN DUSTS. IT IS POSSIBLE THAT THIS ACIO, WHICH WILL

DECOMPOSE THE SILlCATE MINERALS BUT WILL NOT ATTACK THE QUARTZ. WOULD BE SUCCESSFUL

FOR BREAKING OOWN THESE SILTSTONES. THIS ACID WAS NOT AVAILABLE FOR THIS STUOY.

PHOTOMICROGRAPHY WAS ACCOMPLISHED BY USING AN AMERICAN OPTICAL COMPANY

PETROGRAPHIC MICROSCOPE WITH EXTENSIÓN TUBES AND A LEICA CAMCRA. THE MAGNIFICATION

FACTOR WAS COMPUTEO BY MEANS OF A FORMULA PRESENTEO BY EASTMAN KOOAK COMPANY (1935,

P. 10) WHICH STATES THAT THE MAGNIFICATION IN USE CAN BE OBTAINED BY MULTIPLYING

THE MAGNIFICATION OF THE OBJECTIVE BY THE MAGNIFICATION OF THE EYEPIECE BY ONE-

TENTH THE CAMERA EXTENSIÓN IN INCHES.

WELL LOCATIONS ARE INCLUOEO WITH THE THIN-SECTION DESCRIPTIONS. CROSS-

SECTIONS WERE PREPAREO BY USINQ ELECTRIC LOGS ANO SAMPLE DATA. FIGURE I (X 36) CROSSED NICOLS FIGURE 2 (X 35) CROSSED NICOLS LOWER SPRABERRY DEAN LAMÍ ÑATEO SILTSTONE LAMÍN ATEO SILTSTONE U.S. SMELTING NO. L SANOIDGE U.S. SMELTING NO. 1 SANOIDGE 8199

FIGURE 3 (X 36) FIGURE 4 (X 36) SAME AS FIGURE 1 SAME AS FIGURE 2 NICOLS NOT CROSSED NICOLS NOT CROSSED

•H

:i ,.rtv

av • >.%

THIN-SECTIONS OF LAI^INAIED SILTSTONE

Jtaar ? CHAPIER i I

LIIHOLOGY

LOWER SPRABEBNY SILT^TOMF

THE LOWER SPRABERRY SILTSTONE IN THE ÁREA COVEREO BY THIS PAPER FITS THE

CLASSIFICATIÓN GIVEN BY GIBSON (1951) AS "LAMINATEO SILTSTONE* AND "SILTSTONE.*

THE LAMINATEO SlLTSTONE, DESCRIBED AS VERY THINLY BEOOED, OR LAMINATEO, WITH

LAMINATIONS I/I6 INCH THICK, IS BEST ILLUSTRATEO BY THIN-SECTIONS PREPAREO FROM

CORES OF THE U. S. SMELTING AND REFINING CoMPANY*S NO. 1 SANDIDGE FROM 8,197 TO

8,230 (PASE 7, FIGURES I AND 3) IN WHICH SOME OF'THE LAMINATIONS ARPEAR TO BE 1/32

INCH THICK. GLBSON (1951, P. 116) GIVES THE COMPOSITION AS 90L( QUARTZ, 5% CAR­

BONATES. AND 5$ SHALE. THESE FIGURES ARE COMPUTEO IN VOLUME, WHEREAS THE WRITER*S

FIGURES FOR THE LAMINATEB SlLTSTONE ARE: 70$ TO B0% QUARTZ, 8% TO lOjE CARBONATE

GRAINS, AND THE OTHER iZ% TO 10]( IS MADE UP OF SILICA CEMENT AND CLAY MINERALS.

THE "SlLTSTONE" CLASSIFIED BY GlBSON (1951, P. 116) AS A "MASSIVE SlLTSTONE" IS

BEST ILLUSTRATEO BY THIN-SECTIONS MADE FROM CUTTINGS FROM THE TURNER ANO DURHAM

No. 1 BOHANON (PAGE 9, FIGURES 5 ANO 7) FROM 8,690 TO 9,390. HE FURTHER DESCRIBES THE SlLTSTONE AS ESSENTlALLY A QUARTZITE, TIGHTLY CEMENTEO WITH ANGULAR, EVENLY SIZED QUARTZ GRAINS COMPRISING ^Sjt OF THE TOTAL VOLUME, CARBONATE GRAINS COMPRISING

Í0%» AND RELATIVELY FRESH FELOSPAR COMPRISING THE REMAlNING 2% OF THE SlLTSTONE.

GRAIN COUNT METHODS USED IN THIS PAPER REVEAL THE FOLLOWING: 70)í ANGULAR TO SUB-

ANGULAR QUARTZ GRAINS, Í2% CARBONATE GRAINS, LESS THAN 1% FELOSPAR GRAINS, ANO WITH THE PORE SPACES COMPLETELY PILLEO BY SILICA CEMENT AND CLAY MINERALS. IN THE

ELEVEN WELLS STUOIED, APPROXIMATELY 90% OF THE THIN-SECTIONS OF THE LOWER SpRABERRY ARE OF THE "SILTSTONE" TYPE AND THE REMAlNING 20]( ARE OF THE "LAMINATEO SlLTSTONE" TYPE.

P6AN SlLIgfTOHK

No PUBLISHEO DETAILED LITHOLOGICAL DESCRIPTION FOR THE DEAN IS AVAILABLE.

THE PRESENT WRITER*S DESCRIPTION IS AS FOLLOWS: 101( TO V5% LAMÍ ÑATEO SILTSTONE

BEST ILLUSTRATEO (PLATE I, FIGURES 2 AND 4) BY THE 8.338 TO 8,365 CORE INTERVAL OF

THE U. S. SMELTING ANO REFINING COMPANY'S NO. I SANOIDGE; 85$ TO 90$ MASSIVE SILT­

STONE BEST ILLUSTRATEO (PLATE II, FIGURES 6 AND 8) BY THE 8.700 TO 8,900 SAMPLE 8 INTERVAL OF THE ClTIES SERVICE NO. 1 GREQORY.

LAMINATEO SILTSTONE: SU8-ANQULAR QUARTZ GRAINS MAKE UP 75$ TO 80$ OF THE TOTAL NUMBER OF GRAINS, CARBONATE 8$ TO 12$, FELDSPARS LESS THAN 1$ ANO SILICA

CEMENT ANO CLAY MINERALS ACCOUNT FOR THE OTHER 8$ TO 12$. CHLORITE, MICROCLINE

AND PLAGIOCLASE FELOSPAR, TOURMALINE, PYROLUSITE, RUTILE, ZIRCON ANO MUSCOVITE ARE

PRESENT IN SMALL PERCENTAGES (LESS THAN 1$ IN TOTAL). HANO SPECIRENS OF THIS LAMINATEO SILTSTONE ARE GRAY TO DARK BROWN. EXTREMELY FINE GRAINED WITH LAMINATIONS

1/16 TO 1/32 OF AN INCH IN THICKNESS. BREAKS ARE ROUGHLY PARALLEL TO THE

LAMINATIONS.

MASSIVE SILTSTONE: 65$ TO 70$ OF THE GRAINS ARE SUB-ANGULAR QUARTZ

GRAINS OF UNIFORM SIZE AND SHAPE, TIGHTLY CEMENTEO. CARBONATE GRAINS AVERAGE ll>r TO 15$ OF THE TOTAL. PLAGIOCLASE AND MICROCLINE FELOSPAR, MUSCOVITE, TOURMALINE, CHLORITE. PYROLUSITE, RUTILE, AND ZIRCON ARE PRESENT INTERMITTENTLY, BUT NEVER

ACCOUNT FOR AS MUCH AS 1$ OF THE TOTAL. OPALINE SILICA CEMENT ANO CLAY MINERALS COMPLETELY FILL ALL THE PORE SPACES OF THE SILTSTONES. UhOER A BINOCULAR MICROSCOPE THIS SlLTSTONE APPEARS GRAY TO BROWN ANO EXTREMELY FINE GRAlNEO.

THE THICKNESS OF THE DEAN SlLTSTONE IN THE ELEVEN WELLS STUOIED AVERAGES APPROXIMATELY 240 FEET FOR THE BASIN OF FOREREEF WELLS AS WELL AS FOR THE BACKREEF

WELLS. FOR WELLS ORILLEO ON OR NEAR THE REEF PROPER, THE THICKNESS VARÍES FROM

20 FEET TO 200 FEET. IHESE VARIATIONS IN THICKNESS ARE SHOWN IN CROSS-SECTION

A-A*, 6^8* ANO C-C*. CROSS^SECTION 6-B* SHOWS A OISTORTED FOREREEF STRUCTURAL

PICTURE INOICATING A GENTLE 01P. THE WRITER HAS PREVIOUSLY PREPAREO STRUCTURAL

CONTOUR MAPS ON THE TOPS OF THE DEAN AND THE PERMO-PENNSYLVANI AN REEF AND I SOPACH

MAPS OF THE DEAN TOP TO REEF TOP INTERVAL AND OF THE REEF INTERVAL AND HAS FOUNO

THAT THE STRUCTURAL RELATIONS SHOWN BY CROSS-SECTION A-A« AND C-C« ARE MORE NEARLY

CORRECT. IHESE CROSS-SECTIONS ARE PRESENTEO PRIMARILY TO ILLUSTRATE THE STRATI­

GRAPHIC RELATIONSHIP BETWEEN THE LOWER SpRABERRY AND THE DEAN.

THE LITHOLOGIC SIMILARITIES OF THE TWO SILTSTONES INDÍCATE THAT THEY ARE

A COMMON LITHOLOGIC UNIT. STRATIGRAPHIC NOMENCLATURE FOR THE TWO SILTSTONES WOULD

BE LESS CONFUSING IF IT IMPLIEO THAT THEY WERE THE SAME OR SIMILAR LITHOLOGICALLY.

THIS COULO BE ACCOMPLISHED BY ENLARGING THE PRESENT "SPRABERRY FORMATION" TO IN-

CLUDE THE DEAN SlLTSTONE ANO THE OVERLYING WbLFCAMP LIMESTONE WITH THE TWO

BECOMING "MtMBERS" OF THE SPRABERRY FORMATION. FiGURr - ':•: 3 ,i "RCSSED f-iccLs FIGURE 6 (X 36) CROSSED NICOLS LOWER ^; Avt» ..v DEAN MASSIVE SILTSTONE f^ASSIVE SlLTSTONE LURNER DURHAM NO. 1 BOHANON CI TI ES SERV. NO. 1 GREGORY 9350-90 8800-50

flGURf 7 {X 36) FIGURE 8 (X 36) SAME AS FIGURE C NlC'wLS NOT CROSSED NICOLS NOT CROSSED

'•Í:ͻͻ.-5'' 1 *j:; / .r-'

THIN-SECTIONS OF MASSIVE SILISICWE L

Gí"' ) V'}*f M i .ikii\Uii%lÜ\t,.i,iÍ CH..?T£R III

PEIROGRAPHY

PETROGRAPHY OF THE LOWER SPRABERRY SlLTSTONE ANO THE DEAN SlLTSTONE WAS

DETERMINEO FROM A STUOY OF MICROSCOPIC THIN-SECTIONS MADE FROM CORES ANO ROTARY

CUTTINGS. THE FOLLOWING WEÍ.LS WERE STUDIEO:

ClTIES PROOUCTION CORP- 1-8 LEVERETT OAWSON COUNTY

DELHI NO. 1 OlL DEVELOPMENT CO. GAINES COUNTY

R. H. FULTON ET AL NO. 1, C. E. EUBANK TERRY COUNTY

ClTIES PROOUCTION CORP. NO. 1 STARNÉS "D" TERRY COUNTY FREO TURNEN, JR., AND LYNN D. DURHAM NO. 1 LuTNER BOHANON ET AL TERRY COUNTY

AMERADA NO. 1 N.W. WILLARO IiRRY COUNTY

TEXAS CRUDE NO. 2-95 CLASSEN DAWSON COUNTY

ClTIES SERVICE NO. l GREGORY LYNN COUNTY

U. S. SMELTING AND REFINING NO. 1 SANOIDGE DAWSON COUNTY

ALSABROOK No. 1 DUNN GAINES COUNTY

HALL AND STEWART DRLG. NO. I KLATTENHOFF GAINES COUNTY

LOam SPRAKRKY SI LISTONE

QUARTZ. QUARTZ IN THE FORM OF SUB-ROUNOED TO ANGULAR GRAINS IS THE

PREOOMINANT MINERAL OF THE LOWER SPRABERRY SLLTSTONE. MOST OF THE GRAINS ARE SUB-

ANGULAR TO ANGULAR AND ARE GENERALLY CLEAR, BUT SOME GRAINS SHOW A FAINT YELLOW

TINT. THE QUARTZ GRAINS RANGE IN SIZE FROM 2 MICRONS TO 1 MILLIMETER. AND ACCOUNT

FOR AN AVERAGE OF 70$'OF THE TOTAL NUMBER OF GRAINS PRESENT. INTERMEDÍATE SIZES

FROM .05 TO .08 MILLIMETER ACCOUNT FOR 90$ OF THE GRAINS. APPROXIMATELY 10$ OF THE

GRAINS HAVE MICROLITIC INCLUSI0N8 OF GAS BUBBLES, TOURMALINE, RUTILE, ANO ZIRCON.

APPROXIMATELY 90$ OF THE GRAINS HAVE THIN FILMS OF SECONDARY OVERGROWTHS. IHE QUARTZ

GRAINS OF THE LOWER SPRABERRY SlLTSTONE HAVE A MARKEO SIMILARITY TO THE QUARTZ GRAINS

OF THE DEAN SILTSTONE. SPHERICITIES RANGE FROM .59 TO .73. 11

OCAL. IHIS MINERAL IS PRESENT IN THE FORM OF THIN OVERBROWTH FILMS

ON THE QUARTZ GRAINS. NO GRAINS WITH MORE THAN ONE 0VER6R0WTH FILM WERE FOUND.

OPAL IS ALSO PRESENT AS THE CEMENTINQ MATERIAL FOR THIS SILTSTONE. IT IS CLEAR TO

DARK BROWN AND COMPLETELY FILLS ALL PORE SPACES. THE BROWN COLOR IS PROBABLY DUE TO VARYIN6 AMOUNTS OF IRON OXIDE PRESENT IN THE MATRIX. SOME SPINES HAVE BEEN

PARTIALLY TO TOTALLY REPLACED BY OPAL.

CHALCEDONY. THE FIBROUS VARIETY OF THIS MINERAL IS FOUND AS A FILLING

FOR SMALL FRACTURES REPLACING CACCIUM CARBONATE AND RARELY AS A REPLACEMENT FOR SPINES AND OTHER FOSSIL FRAGMENTS.

CARBONATES. CARBONATE GRAINS COMPRISE FROM 2$ TO 12$ OF THE TOTAL

NUMBER OF GRAINS WHEN PRESENT. IHEY OCCUR AS ISOLATED RHOMBS AND IRREGULAR GRAINS.

TRANSLUCENT CLEAR TO BUFF IN COLOR. SOME THIN-SECTIONS CONTAIN ISOLATED. RAGGED

RHOMBS WHICH ARE POSSIBLY DOLOMITE. BECAUSE OF THE MICROSCOPIO SIZE OF THESE

RHOMBS NO DETERMINATIVE TESTS WERE MADE. FRAGMENTS OF FOSSILS REPLACED BY CARBONATES ARE RARE IN THE SlLTSTONE. CARBONATES ARE PRESENT AS OOLITES IN THE ClTIES PROO. CORP. No. l-B LEVERETT REPRESENTING A BACKREEF TYPE DEPOSIT.

OTHER MINERALS. OTHER MINERALS PRESENT INCLUDE FELOSPAR. HEMATITE. MAQNETITE, MUSCOVITE, SERICITE. CHLORITE. PYROLUSITE, TOURMALINE, ZIRCON. RUTILE,

GLAUCONITE AND GARNET. ZiRCON, RUTILE, MAGNETITE, GLAUCONITE AND GARNET ARE RARE, AND SERICITE, CHLORITE ANO PYROLUSITE ARE LOCALLY ABUNDANT. FELOSPAR OCCURS AS ANGULAR GRAINS OF MICROCLINE ANO PLAGIOCLASE. SOME GRAINS ARE PARTIALLY REPLACED BY SILICA AND OTHERS SHOW ALTERATION AROUND THE GRABN E06ES ONLY. PLAGIOCLASE IS THE PREOOMINANT FELOSPAR OCCURRING IN 61$ OF THE THIN- SECTIONS STUOIED. MICROCLINE OCCURS IN 10$ OF THE THIN-SECTIONS WHEN PRESENT. THE FELOSPAR GRAINS REPRESENT AN AVERAGE OF .03$ OF THE TOTAL NUMBER OF GRAINS.

HEMATITE OCCURS AS IRREGULAR, ISOLATED, REDDISH BROWN, TRANSLUCENT FLAKES, ANO AMORPHOUS MASSES WHICH IN SOME THIN-SECTIONS HAVE A RESINÓOS APPEARANCE. iHE LAMINAE IN THE SlLTSTONE ARPEAR TO CONTAIN CONCENTRATIONS OF HEMATITE.

MAGNETITE IS RARE, OCCURRING AS ANGULAR TO SUB-ANGULAR. BLACK, ISOLATED,

DETRITAL GRAINS. MUSCOVITE WHEN PRESENT, OCCURS AS CLEAR, IRREGULAR, ISOLATED FLAKES COMPRISING AN AVERAGE OF .008$ OF THE TOTAL GRAlN COUNT.

SERICITE OCCUR*; AS MINUTE GRAINS DISSEMINATED THR0U6H0UT THE MATRIX 12

ASSOCIATED WITH OTHER CLAY MINERALS. THIS MINERAL WAS DESCRIBED AS ILLITE BY

SCHMITT (1954. P. 1964).

CittA&ilLi OCCURRING AS ISOLATED. RAGGED TO IRREGULAR PALÉ GREEN GRAINS,

COMPRISES AN AVERAGE OF .005$ OF THE TOTAL GRAIN COUNT WHEN PRESENT ANO APPEARS IN

18$ OF THE THIN-SECTIONS STUOIED. IT IS OF METAMORPHIC ORIGIN.

PYROLUSITE. LOCALLY ABUNDANT AS SMALL BLACK SPHERICAL AGGREGATES AND

CLUSTERS OF SPHERICAL AGGREGATES. THIS MINERAL IS PRESENT IN 8$ OF THE THIN-SECTIONS

STUOIED. IT HAS BEEN CLASSIFIED AS AN AUTHIGENIC SEDIMENTARY MINERAL BY WARN AND

SlOWELL (1953, P. 71).

TOURMALINE APPEARS CLEAR TO LIGHT GREEN IN THIN-SECTIONS AS CRYSTAL

FRAGMENTS, SOME WELL-WORN AND SOME WITH OISTINCT STRIATIONS. SOME OF THE ISOLATED

CRYSTAL FRAGMENTS SHOWING OISTINCT STRIATIONS MAY HAVE BEEN BROKEN OUT AS QUARTZ

INCLUSIONS DURING TRANSPORTATION. IHE WELL-WORN GRAINS MAY OR MAY NOT HAVE BEEN

INCLUSIONS. TOURMALINE IS ALSO PRESENT AS INCLUSIONS IN QUARTZ. ISOLATED TOURMA­

LINE CRYSTAL FRAGMENTS ARE PRESENT IN 8$ OF THE THIN-SECTIONS STUOIED.

¿I££Í2IL> FOUND IN 4$ OF THE THIN-SECTIONS STUOIED. IS RARE AS CLEAR

SUB-ANGULAR FRAGMENTS, SHORT CRYSTALS, AND ELONGATE CRYSTAL FRAGMENTS, SOME WITH

ROD-LIKE INCLUSIONS.

GUUI^, PRESENT IN 2$ OF THE THIN-SECTIONS STUOIED, OCCURS AS YELLOW

TO BROWN, ELONGATE CRYSTAL FRAGMENTS, AND AS INCLUSIONS IN QUARTZ. SOME CRYSTAL

FRAGMENTS SHOW CONSIDERABLE ROUNDING.

GLAUCONITE OCCURS AS PALÉ GREEN PLEOCHROIC SPHERICAL MASSES IN .5$ OF

THE SLIDES STUDIEO ANO IS CONSIOERED OF LOCAL OCCURRENCE AND FORMED IJI SITU.

^ABBCL OCCURS IN ONE THIN-SECTION AS PARTIALLY ROUNOED, AMBER COLOREO,

ISOLATED GRAINS.

ORGANIC MATERIALS. ORGANIC MATERIALS ARE VERY POORLY PRESERVEO IN THE

LOWER SPRABERRY IN THE ÁREA COVEREO BY THIS PAPER ANO ARE PRESBNT CHIEFLY AS

FRAAMENTS. SPINES, ALGAL FRAGMENTS ANO RADIOLARIA ARE PRESENT, AS IS ALSO SOME

UNÍDENTIFIABLE CARBÓNIZED MATERIAL WHICH APPEARS AS IRREGULAR AMORPHOUS PATCHES ANO

FRAGMENTS. THE TRANSPARENT SPINES HAVE AN ELONGATE NEEDLE-LIKE FORM ANO A OOUBLE

WELL. SOME SPINES ARE PARTIALLY TO TOTALLY REPLACED BY SILICA. IHE ALGAL FRAGMENTS

ARE PRESENT AS SPHERES ANO TNIN VEIN-LIKE FRAGMENTS WHICH SHOW SOME REPLACEMENT BY

CHALCEDONY. FRAOMENTS WITH FUSULINIO-LIKE OUTLINES ARE PRESENT BUT UNÍDENTIFIABLE. 13

FRAGMENTS OF BRY20ANS ARE PRESENT BUT ALSO UNIDENTIFIABLE.

DEAN SILTSTTHNE

QUABLL* SUB-ROUNDED TO ANGULAR QUARTZ GRAINS ARE THE PREOOMINANT

MINERAL OF THE DEAN SlLTSTONE. MOST OF THE GRAINS ARE SUB-ANGULAR TO ANGULAR AND

ARE GENERALLY CLEAR, BUT SOME SHOW A FAINT YELLOW TINT. GRAIN SI ZES RANGIN6 FROM

2 MICRONS TO 1 MILLIMETER ACCOUNT FOR 65$ TO 70$ OF THE TOTAL NUMBER OF GRAINS

PRESENT. APPROXIMATELY 90$ OF THE GRAINS RANGE FROM .05 T0..08 MILLIMETER. 10$ OF

THE QUARTZ GRAINS HAVE MICROLITIC INCLUSIONS, INOICATING AN IGNEOUS ORIGIN FOR

THESE GRAINS. APPROXIMATELY 90$ OF THE GRAINS HAVE THIN FILMS OF SECONDARY OVER­

GROWTHS. THE QUARTZ GRAINS OF THE DEAN HAVE A MARKED SIMILARITY TO THE QUARTZ

GRAINS OF THE LOWER SpRABERRY. QCAk. OPAL IS PRESENT IN THE FORM OF THIN OVERGROWTH FILMS ON THE QUARTZ GRAINS, BUT NO GRAINS WITH MORE THAN ONE OVERGROWTH FILM WERE FOUND. QpAL

IS ALSO PRESENT AS THE CEMENTING MATERIAL APPEARING CLEAR TO OARK BROWN AND COMPLETELY FILLING ALL PORE SPACES. IHE BROWN COLOR IS PROBABLY DUE TO VARYING AMOUNTS OF IRON OXIDE IN THE MATRIX. SOME SPINES HAVE BEEN PARTIALLY TO T01ULLY REPLACED BY OPAL.

CHALCEDONY. FIBROUS CHALCEDONY OCCURS RARELY AS A REPLACEMENT FOR SPINES AND OTHER FOSSIL FRAGMENTS.

CARBONATES. CARBONATE GRAINS COMPRISE FROM 2$ TO 15$ OF THE TOTAL

NUMBER OF GRAINS WHEN PRESENT. IHEY OCCUR AS ISOLATED RHOMBS AND IRREGULAR GRAINS,

TRANSLUCENT CLEAR TO BUFF IN COLOR. ISOLATED RHOMBS IDENTIFIED AS CALCITE ARE

POSSIBLY DOLOMITE, BUT ON AECOUNT OF THEIR MICROSCOPIO SIZE. NO DETERMINATIVE TESTS

WERE MADE. FRAGMENTS OF FOSSILS REPLACED BY CARBONATES ARE RARE IN THE SlLTSTONE.

QTHER MINERALS. OTHER MINERALS PRESENT INCLUDE FELOSPAR, HEMATITE,

MAGNETITE, MUSCOVITE, SERICITE, CHLORITE, PYROLUSITE, TOURMALINE, ZIRCON AND RUTILE.

FELOSPAR OCCURS AS ANGULAR GRAINS OF MICROCLINE AND PLAGIOCLASE. SOME

GRAINS ARE PARTIALLY REPLACED BY SILICA AND OTHERS SHOW ALTERATION AROUND THE GRAIN

EDQES ONLY. PLAGIOCLASE IS THE PREOOMINANT FELOSPAR OCCURRING IN 63$ OF THE THIN-

SECTIONS ITUOIED. MICROCLINE OCCURS IN 10$ OF THE THIN-SECTIONS, WHEN PRESENT.

THE FELOSPAR GRAINS REPRESENT AN AVERAGE OF .03$ OF THE TOTAL NUMBER OF GRAINS. 14 HEMATITE OCCURS AS IRREGULAR. ISOLATED. REDDISH BROWN. TRANSLUCENT

FLAKES. ANO AMORPHOUS MASSES. IHE LAMINAE IN THE SlLTSTONE APPEAR TO CONTAIN

CONCENTRATIONS OF HEMATITE.

MAGNETITE |S RARE. OCCURRING AS ANGULAR TO SUB-ANGULAR. BLACK, ISOLATED

DETRITAL GRAINS.

MUSCOVITE OCCURS AS CLEAR, IRREGULAR, ISOLATED FLAKES COMPRISING AN

AVERAGE OF .01$ OF THE TOTAL NUMBER OF GRAINS WHEN PRESENT.

SERICITE OCCURS AS MINUTE GRAINS DISSEMINATED THR0U6H0UT THE MATRIX,

ASSOCIATED WITH OTHER CLAY MINERALS.

CHLORITE OCCURRINQ AS ISOLATED, RAGGED TO IRREGULAR, PALÉ GREEN GRAINS

IN 28$ OF THE THIN-SECTIONS STUOIED, COMPRISES AN AVERAGE OF .005$ OF THE TOTAL

NUMBER OF GRAINS WHEN PRESENT. IT IS OF METAMORPHIC ORIGIN.

PYROLUSITE. OCCURRING IN 7$ OF THE THIN-SECTIONS STUOIED. IS LOCALLY

ABUNDANT AS SMALL BLACK SPHERICAL AG6RGQATES AND CLUSTERS OF SPHERICAL AGGREGATES.

IT IS CLASSIFIED AS AN AUTHOGENIC SEDIMENTARY MINERAL.

TOURMALINE APPEARS CLEAR TO LIGHT GREEN IN THIN-SECTIONS AS CRYSTAL

FRAGMENTS, SOME WELL-WORN AND SOME WITH OISTINCT STRIATIONS. SOME OF THE ISOLATED

CRYSTAL FRAGMENTS SHOWING DISTiNCT STRIATIONS MAY HAVE BEEN BROKEN OUT AS QUARTZ

INCLUSIONS DURING TRANSPORTATION. THE WELL-WORN GRAINS HAY OR MAY NOT HAVE BEEN

INCLUSIONS. TOURMALINE IS PRESENT ALSO AS INCLUSIONS IN QUARTZ. 1SOLATED TOURMA­

LINE CRYSTAL FRAGMENTS ARE PRESENT IN 15$ OF THE THIN-SECTIONS STUDIEO.

ZIRCON. FOUNO IN 2$ OF THE THIN-SECTIONS STUOIED. OCCURS RARELY AS

CLEAR. SUB-ANGULAR FRAGMENTS, SHORT CRYSTALS, AND ELONGATE CRYSTAL FRAGMENTS. SOME

WITH ROD-LIKE INCLUSIONS.

RUTILE, PRESENT IN 6$ OF THE THIN-SECTIONS STUDIEO, OCCURS AS YELLOW TO

BROWN, ELONGATE CRYSTAL FRAGMENTS AND AS INCLUSIONS IN QUARTZ. SOME CRYSTAL

FRAGMENTS SHOW CONSIDERABLE ROUNDING. ORGANIC MATERIAL. ORGANIC MATERIAL IN THE DEAN CONSISTS OF SPINES,

ALGAL FRAGMENTS ANO RADIOLARIA. SpINES AND RADIOLARIA SHOW PARTÍ AL TO TOTAL

REPLACEMENT BY SILICA. ORAANIC MATERIALS ARE MORE COMMON IN LIMESTONE ANO SHALE

WHICH ARE ASSOCIATED WITH THE OEAN ANO ARE FOUNO VERY RARELY IN SlLTSTONE. PETROGRAPHIC COMPARISONS

<^ARTZ FOUND IN THE LOWER SpRABERRY AND IN THE DEAN SILTSTONES IS

ALMOST lOENTICAL. THE SLIGHT VARIATION IN GRAIN COUNT IS OF NO CONSEQUENCE SINCE

IT PROBABLY REPRESENTS SORTING VARIATIONS DUE TO CHANGES IN OEPOSITIONAL CONOITIONS.

BECAUSE OF THE SIZE OF THE GRAINS, SPHERICITIES YIELD ONLY COMPARATIVE DATA FOR

BOTH THE LOWER SpRABERRY ANO THE DEAN RATHER THAN AN INDICATION OF THE TRANSPOR­

TATION RECORD AS MIGHT BE EXPECTED FROM SPHERICITES OF LAR6ER GRAINS. THE PER CENT

OF SPHERICITY ATTAINED BY THESE QUARTZ GRAINS PRIOR TO LITHIFICATION IS AN

INDICATION OF A LONG HISTORY OF RE-WORKING. WARN AND SiDWELL (1953, P. 71) NOTE

THE SMALLNESS. ANGULARITY. ANO PITTING OF GRAINS AS TYPIFYING PARTEÓLES CARRIEO IN

WATER SUSPENSIÓN. SIMILAR CHARACTERISTICS ARE EXHIBITED BY ISOLATED QUARTZ GRAINS

IN PIECES OF LIMESTONE FROM THE LOWER SPRABERRY INTERVALS FROM THE FOLLOWING WELLS! DELHI NO. I OIL DEVELOPMENT CO. 8.900-50. CITIES PROD. NO. I-B LEVERETT 8,250-OO, AMERADA NO. I NW WILLARO 7.800-60. THIS FACT HAS CAUSEO THE WRITER TO CONSIDER THE

POSSIBILITY OF AEOLIAN OEPOSITION AS AN ADDITIONAL CONTRIBUTING TRANSPORTATION

FACTOR. IF ONE ASSUMES AEOLIAN OEPOSITION FOR THESE ISOLATED QUARTZ GRAINS IN THE

LIMESTONE ASSOCIATED WITH THE LOWER SPRABERRV, ONE MIGHT ALSO ASSUME THE SAME

ORIGIN FOR AT LEAST A PART OF THE QUARTZ GRAINS WITH THE SAME CHARACTERI STICS IN

THE SILTSTONES. THIS ASSUMPTION WOULD PROBABLY APPLY TO THE DEAN SILTSTONE ALSO.

A PETROGRAPHIC STUOY OF THE TWO SILTSTONES FROM WELLS OVER THE ENTIRE MlDLAND

BASIN SHOULD BE MADE BEFORE ANY PRECISE CONCLUSIONS ARE REACHEO, BUT THE EVIOENCE

PRESENTEO IN THIS PAPER SUGGESTS THAT THE AMOUNT OF GRAINS TRANSPORTED AND DE-

POSITEO IN THIS MANNER MIGHT BE SIGNIFICANT. THE TOTAL SIMILARITIES OF THE QUARTZ

GRAINS ARE INDICATIVE OF A COMMON SOURCE.

OPAL OCCURRING AS THE PRINCIPAL CEMENT IN BOTH SILTSTONES WITH

LOENTICAL CHARACTERISTICS IS INDICATIVE OF A SIMILARITY IN CONOITIONS AFTER

OEPOSITION.

THE SIMILARITY OF THE CARBONATE GRAINS IN BOTH THE LOWER SpRABERRY AND

THE DEAN SILTSTONE IS FURTHER EVIOENCE OF SIMILAR CONDITIONS AFTER OEPOSITION AS

WELL AS AN INDICATION OF SIMILARITY OF CONOITIONS EXISTING DURING OEPOSITION.

THE COMMON OCCURRENCE OF MICROCLINE AND PLAGIOCLASE FELOSPAR, HEMA­

TITE, MAGNETITE, MUSCOVITE, CHLORITE, PYROLUSTTE, TOURMALINE, ZIRCON, RUTILE, IS 16

ADDITIONAL EVIOENCE OF A COMMON SOURCE. GLAUCONITE FOUNO IN THE LOWER SPRABERRY

IS CONSIOERED OF LOCAL OCCURRENCE. GARNET FOUND IN THE LOWER SPRABERRY IN ONE

SLIDE ONLY IS NOT CONCLUSIVE EVIOENCE OF PERSISTEMT OCCURRENCE. THE FACT THAT

THESE MINERALS, EXCEPT FOR THE GLAUCONITE, ARE STABLE FORMS INDICATES A LONG

HISTORY OF REWORKING. ISOLATED TOURMALINE CRYSTALS WITH DISTINCT STRIATIONS WERE

PROBABLY BROKEN OUT AS QUARTZ INCLUSIONS DURING TRANSPORTATION.

THE OCCURRENCE OF SUCH STABLE MINERALS AS CHALCEDONY, QUARTZ. RUTILE,

ZIRCON, SECONDARY HEMATITE, ANO SUCH MODERATELY STABLE MINERALS AS PLAGIOCLASE AND

MICROCLINE FELOSPAR IS AN INDICATION OF REI^ORKINQ.

QUARTZ WITH MICROLITIC INCLUSIONS AND THE PRESENCE OF MUSCOVITE,

ZIRCON AND PLAGIOCLASE FELOSPAR ARE INDICATIVE OF AN ACID IGNEOUS PARENT ROCK.

THE TWO PRECEDÍNG INDICATIONS SUQGEST THAT THE LOWER SPRABERRY AND

DEAN SILTSTONES WERE OEPOSITEO AS A RESULT OF THE REWORKING OF PRE-EXISTING

SEDIMENTS WHICH WERE FROM AN ACID IGNEOUS SOURCE.

BECAUSE OF THE ABOVE PETROGRAPHIC SIMILARITIES WHICH ARE INDICATIONS OF A COMMON SOURCE ANO INDICATIONS OF THE EXISTENCE OF SIMILAR CONDITIONS PRIOR TO, DURING, ANO AFTER OEPOSITION, IT APPEARS THAT THESE TWO SILTSTONES SHOULD BE INCLUOEO IN THE SAME LITHOLOGIC UNIT. THE PRESENT USAGE OF THE TERMS SpRABERRY

AND DEAN, WHICH IMPLIES THAT THE TWO ARE SEPÁRATE LITHOLOGIC UNITS, IS MiSLEADING. cmwp IV

CONaUSIONS

1. OM THE BASIS OF THE EVIDENCES SHOWN IN THIS PAPER, IT IS ASSUMED THAT NO

DISTINCTION CAN BE MADE BETWEEN THE LOWER SPRABERRY SlLTSTONE ANO THE DEAN SlLTSTONE BY MEANS OF A PETROGRAPHIC STUOY.

2. SPHERICITIES HAVE PROVEO OF NO VALUÉ IN DISTINGUISHING BETWEEN THE TWO SILTSTONES, BUT THE SIMILARITY IN THEIR SPHERICITY VALÚES IS AN INDICATION OF SIMILAR HISTORIES.

3. TOTAL SIMILARITIES OF THE QUARTZ GRAINS ARE INDICATIVE OF A COMMON SOURCE FOR THE TWO SILTSTONES AND OF SIMILARITIES IN CONDITIONS EXISTING DURING AND AFTER OEPOSITION.

4. BECAUSE OF THE GROSS SIMILARITIES IN THE TWO SILTSTONES, IT IS BELIEVEO

THAT THE LOWER SpRABERRY AND THE DEAN SILTSTONES WERE OERIVED FROM SIMILAR ACID IGNEOUS SOURCES.

5. BECAUSE OF THESE SIMILARITIES, THE WRITER PROPOSES THAT THE LITHOLOGIC

UNIT PRESENTLY CALLEO THE SPRABERRY FORMATION BE ENLARGED TO INCLUDE THE OEAN SlLTSTONE ANO THE OVERLYING WOLFCAMP LIMESTONE WITH THE TWO BECOMING THE LOWER

"MEMBERS" OF THE SPRABERRY FORMATION. THIS MORE INCLUSIVE TERM "SPRABERRY

FORMATION" WOULD BE INDICATIVE OF A LITHOLOGIC UNIT RATHER THAN OF A TIME UNIT.

6. BASEO ON THE PRECEDÍNG ASSUMPTIONS, IT IS POSSIBLE THAT THE SANOS ANO SILT­

STONES NOW PRESENT AS SpRABERRY ANO DEAN REPRESENT CONTINUÓOS OEPOSITION WITH THE

STRATIGRAPHIC LIMESTONE AND SHALE BREAKS REPRESENTING FACIES CHANGES. PRESENT DATA

HOWEVER, ARE INSUFFICIENT TO SUPPORT THIS CONCLUSIÓN.

7. THE WRITER CONCLUOES THAT A OETAILED STÜDY OF THE CLAY MINERALS BY X-RAY

ANALYSIS WOULD BE OF A GREAT VALUÉ IN ENLARGING THE PRESENT DATA ON THE SPRABCRRY

ANO THE DEAN SILTSTONE ANO POSSIBLY IN PROVIOING A MEANS TO MORE OEFINITE

CORRELATIONS FOR THE TWO SILTSTONES. REFERENCFS n^Jf^Q

ANOERSON, KENMETH C., (1953) •WELLMAN FÍELO, TERRY COUNTY, TEXAS," AMER. ASSQC. EttaOL. QEfiLAftLSI&. BULL., VOL. 37, No. 3. PP. 509-21. ^^

BARTLEY, J. H., (1951) "THAT SPECTACÜLAR SPRABERRY. A SYMPOSIUM- PART 3: 5TRATIGRAPHY AND STRUCTURE OF THE SPRABERRV TREND." QJLL AHft fiáft «áUA* . VOL. 50, No. 31, PP. 101 AND 112.

EASTMAN KbOAK COMPANY (19J») •pHPTOHICWMBAPHY'Att INTRODUCTION ^ PHOTOCRAPHY HUM gtti^MtCnPKOPEf THIRTEENTH EDITION, EASTMAN »(DDAK COMPANY, IBCISTER,

GlBSON, GEORGE R., (1951) "TlAT SPECTACULAR SPRABERRY, A StMPOSIUM-PART 2: ^LATION OF FRACTURES TO THE ACCUMULATION OF OIL," OIL ABC GAÍ JOUW.. VOL. 50, NO. 30, PP. 107 AND 116-117. ««^ an^c na» MUB KMOPF, ADOLPH (1953) "THE QUANTITATIVE DETERMINATION OF QUARTZ (FREE SILICA) IN DUSTS," U. S. TREASURY OEPT., PUBLIC HEALTH REPQRTS. VbL. 48, No. 8

KORNFIELD, JOSEPH A., (1952) "WELLMAN REEFJ 2 MlLLlON BARRELS IN 2 YEARS," QIL AND QA& JfiU&.« VOL. 51, No. 24, pp. 135-142.

MCLENNAN, LANAR, JR., AND BRAOLEY, H. WARING, (1951) "SPRABERRY AND DEAN SANDSTONES OF WEST TEXAS," éttL&*..ÁSSfi£.* PETRQL. GEOLOGISTS. BULL., VDL. 35. No. 4, pp. 899-915.

MARSHALL, JOSEPH W., (1952) "SPRABERRY RESERVOIR OF WEST TEXAS," UMER. ASSQC. PSTTOL* GEOLOGISTS. guLL., VOL. 36, No. 11, PP. 2189-2191.

OSBORN, W. M., (1951) "THAT SPECTACÜLAR SPRABERRY, A SYMPOSIUM, PART 3: HISTORY AND DEVELOPMENT OF THE SPRABERRY TRENO," QXJL éhk (iA& Jo UN- t VOL. 50, NO. 31, pp. 100-101.

RlTTENHOUSE, GORDON, (1943) "A ViSUAL METHOO FOR ESTIMATING TwO-OlMENSIONAL SPHERICITY," Jaua. Sl&fi* PETWOLOGY. VOL. 13, PP. 79-81.

SCHMITT, GEORGE T., (1954) "GÉNESIS AND DEPOSITIONAL HISTORY OF SPRABERRY FORMATION, MiOLAND BASIN, TCXAS," éas^. ASSQ£* EOfiOL» GEOLOGISTS. BULL.» VOL. 38, No. 9, pp. 1957-1978.

WARN, G. FREOERICK, CARMACK, ROY P., ANO SIOWELL, RAYMONO (19S2) "REGIONAL SUB­ SURFACE GEOLOGY OF THE MIDLAND BASIN," QIL tMÜ (ÍA& iÍBÚ&*> VOL. 51, No. 24, pp. 113-114, 116-118, 121-122.

WARN, G. FREDERICK, (1953) "SPRABERRY STRUCTURAL CONOITIONS," PART 1, íbBLSL QiLt VbL. 136, NO. 4, pp. 83-66 AND 88, PART 1, jflfQBLfi Qikt >foi- 136, No. 5, pp. 100, 102 AND 104.

WARN, G. FREDERICK, AND SIDWELL, RAYMOND (1953) "PETROLOGY OF THE SPRABERRY SANOS OF WkST TCXAS," ijQUa» ¿Lfi* PFTRQLOGY. VOL. 23, No. 2, pp. 67^74.

WiLKiNSON, WALTER M. (1953) "FRACTURING IN SPRABERRY RESERVOIR, WEST TEXAS," ÉtíL» Assoc. PETRQL. GEOLOGISTS. BULL., VOL. 37, No. 2, PP. 250-265. APPENDIX Í&*Tl#». C"** Tj!"^"» JR.j^AMO LVMN 0. DURNAM |l. LUTMER BONANOH ET AL. LCJCATION: Tv^Comrr (1980» FSL AUO 660» FEL OF SCC, SCC. 74, BLK. DÜ, JPNN H. GlBSON SURVEY)

líOrntL THIN-S£CTI0N "Ll^.lPTlL^AS 8670-00 SlLTSTONE: tsTIMATEO SpHERIClTY .05 yuARTz: ANGULAR TO SUB-ANGULAR; LARQEST GRAINS FOUR DIAMETERS OF SMALLEST GRAINS. NOT IN COMTACT (MATRIX BETWEEN GRAINS) QRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE I RON <"X|DE: AS BROWN ANO BLACK IRREGULAR ISOLATED QRAINS IN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE CTTHER VINERAL: K'ANGANESE DIOXIDE AS BLACK RAGGED GRANULAR MASSES 8700-50 SILTSTONE: ESTIMATED SPHERICITY .66 QUARTZ: ANGULAR TO SUB-ANGULAR; LARQEST GRAINS FOUR DIAMETERS OF WALLEST GRAINS, NOT IN CONTACT (MATRIX BETWCF.N GRAiNS) GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH I NON OXIDF IRON OXIDE: AS BNOWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINF.RALS: PLAGIOCLASC FELOSPAR; MANGANESE DIOXIOE AS DARK RAGGED GRANULAR MASSES 8750-00 SlLTSTONE: ESTIMATED SPHERICITY .^9 QUARTZ: ANGULAR TO SUB-ANGULAR; LARGCST GRAINS FOUR DIAMETERS OF SMALLEST GRAINS, NOT IN CONTACT (MATRIX BETWEEN GRAlNS| GRAINS CONTAIN MICROLITIC INCLUSIONS OPALX CNIEFLV AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIOE ANO OPAL COMPLETELY FILLINB PORE SPACE OTHER MINERALS: PLAGIOCLASE ANO MICROCLINE FELDSPAR; RAGGEO IRREGULAR OARK GRAINS MANGANESE DIOXIOE 8800-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-AMGULAR GRAINS, SOME GRAINS SOMEWHAT NOUNDED BY THICK OVER- «ROWTHS, GRAINS NOT IN COMTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE CALCITE: ISOLATED IRREGULAR FRAGMENTS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

88S0-00 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR GRAINS, SOME GRAINS SOMEWHAT ROUNDED BY THICK OVU- QROWTHS, GRAINS NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS O^ALS CNIEFLV AS CEMENT ASSOCIATED WITH IRON OXIOE CA&AITC: ISOLATED IRREGULAR FRAGMENTS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTNCR MINERAL: PLAGIOCLASE FELOSPAR 28 •900-90 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SU»-ANGULAR GRAINS, MAJORITY OF GRIINS HAVE FILMS OF OVERGROWTHS, GRAINS NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE CALCITE: ISOLATED IRREGULAR FRAQMENTS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE 8950-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR GRAINS. MAJORITY OF GRAINS HAVE FILMS OF OVERGROWTKS, QRAINS NOT IN CONTACT, CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE CALCITE: ISOLATED IRREGULAR FRAQMENTS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE 9000-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR GRAINS, MAJORITY OF GRAINS HAVE FILMS OF OVERGROWTHS, GRAINS NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN ANO BLACK IRREGULAR GRAINS IN MATRIX CALCITE: ISOLATED IRREGULAR FRAQMENTS AND RHOMBS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELOSPAR; PLAGIOCLASE FELOSPAR 9050-00 SILTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR GRAINS, UNÍFORM IN SIZE, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE {RON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR 9100-50 SILTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR GRAINS, UNIFORM IN SIZE, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN ANO BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILÍING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 9150-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR GRAINS, UNIFORM IN SIZE, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS, AGGREGATE CLUSTERS OF ANGULAR GRAINS WHICH APPEAR TO HAVE BEEN FORMED BY THE DISINTEGRATION OF A LARGER QUARTZ FRAGMENT OR GRAIN. OPAL: CNIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE AND PLAGIOCLASE FELDSPAR; IRREGULAR RAGGED DARK GRAINS MANGANESE DIOXIOE 29 9200-50 SlLTSTONE: ESTIMATED SPHERICITY .67 WUARTZ: SUB-ANGULAR GRAINS. EVENLY DISTRIBUTED. GRAINS HAVE THIN OVER­ GROWTHS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXI¿£ IRON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 9250-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SOME GRAINS SHOW EVIOENCE OF STRAINING. SU^ANGULAR GRAINS, UNIFORMLY SLZED, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS. ISOLATED LARGER GRAIN SHOWINQ PARTIAL DISINTEGRATION INTO SMALLER ANGULAR FRAQMENTS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: HAQNESIUM DIOXIOE IN SCATTERED RAGGED DARK GRAINS 9300-50 SILTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR GRAINS, UNIFORHLY SIZEO, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN ANO BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: OLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED RAGGED DARK GRAINS MANGANESE DIOXIOE 9350-90 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR GRAINS, UNIFORMLY SIZEO, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: OIIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN AND BLACK IRREGULAR GRAINS IN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED RAGGED DARK GRAINS MANGANESE DIOXIDE 9814-50 SILTSTONE: ESTIMATED SPHERICITY .67 Q^jARTz: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

9850-00 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED, UNIFORMLY SIZEO, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS, SOME GRAINS WITH THIN FILM OF OVERBROWTH OPAL: CNIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHCR MINERAL: IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE 30 9900-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SU»>ANGULAR GRAINS, EVENLY DISTRIBUTED, UNIFORMLY SIZED, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS, SOME GRAINS WITH THIN FILM OF OVERGROWTH OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; IRREGULAR RAGGED GRAINS MANGANESE DIOIXOE 9950-10,000 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED, UNIFORMLY SIZEO, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS, SOME GRAINS WITH THIN FILM OF OVERGROWTH OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE 10,000-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZEO, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDCX AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATEO GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETEVY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

10,050-100 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL; CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPAVE OTHER MINERAL: PLAGIOCLASE FELDSPAR Ío-l,-^. ?. D. ALSABROOK ll, MRS. W. B. DUNN LC^TION: GAINES COUNTY 6OO« FNL & 660» Fa OF SEC. SEC. 78, DLK. 4, D fc m( SURVEY)

IMmL THtr¿-b£CTIOJ DESCRIPTIONS 9030-50 BROWN LIMESTONE COMPOSED OF ALGAL DETRITUS AND ISOLATED CALCITE RHOMBS IN A CALCIUM

CARBONATE MATRIX

SILTSTONE: ESTIMATED SPHERICITY .73 t^UARTZ: 5U8-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME QRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN AND BLACK ISOLATED GRAINS, ANO AS BROWN LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED PLATES MUSCOVITE 9050-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGM.AR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; BROWN ISOLATED GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MUSCOVITE MICROCLINE FELOSPAR 9100-50 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BROWN GRAINS ANO BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CXAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED PLATES MUSCOVITE; ISOLATED PLAGIOCLASE FELDSPAR GRAINS PARTIALLY REPLACED BY QUARTZ; MICROCLINE FELDSPAR 9150-00 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS ANO BROWN LAMINAE WHICH PROJECT OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED IRREGULAR GRAINS MANGANESE DIOXIOE; PLAGIOCLASE FELDSPAR; ISOLATED PLATES MUSCOVITE; TOURMALINE AS INCLUSIONS IN QUARTZ; FAINT STRIATIONS 9200-SO SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS ANO BROWN LAMINAE WHICH PROJECT OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RNOMBS rnHrí-ir^. r* ^' ALSABROOK ll, MRS. W. B. DUNN LOCATION: GAINES COUNTY (6OO« FNL & 660* FEL OF SEC SEC. 78, DLK. 4, D I, WRR SURVEY)

IhSmL THtr^-SECTICU DESCRIPTIONS 9030-50 BROWN LIMESTONE COMPOSED OF ALGAL DETRITUS ANO ISOLATEO CALCITE RHOMBS IN A CALCIUM

CARBONATE MATRIX

SILTSTONE: ESTIMATED SPHERICITY .73 gUARTZ: Sue-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN AND BLACK ISOLATED GRAINS, ANO AS BROWN LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED PLATES MUSCOVITE 9050-00 SILTSTONE: ESTIMATED SPHERICITY .69 (^ARTZ: SUE-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN ISOLATED GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MUSCOVITE MICROCLINE FELOSPAR 9100-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS ANO THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BROWN GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED PLATES MUSCOVITE; ISOLATED PLAGIOCLASE FELDSPAR GRAINS PARTIALLY REPLACED BY QUARTZ; MICROCLINE FELDSPAR 9150-00 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANOULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS ANO BROWN LAMINAE WHICH PROJECT OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED IRREGULAR GRAINS MANGANESE DIOXIDE; PLAGIOCLASE FELOSPAR; ISOLATED PLATES MUSCOVITE; TOURMALINE AS INCLUSIONS IN QUARTZ; FAINT STRIATIONS

9200-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SU»-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAIMS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BNOWN IRREGULAR GRAINS AND BROWN LAMINAE WHICN PROJECT OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND ISOLATED RHOMBS Síül^L. ^^^* *"2" ^^^^ ^"** ^^'^ COMPLETELY FILLING PORE SPACE OTMER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED PLATES MUSCOVITE 9250-00 ^•JJ.*^o»*^* ^ ESTIMATED SPHERICITY .67 VUARTZ: SUV-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH THIN FILMS OF OVENSNOWTH AND MICROLITIC INCLUSIONS I *"*A ^***^^^^ '^^ CEMENT ASSOCIATED WITH IRON OXIOE IRON OXIDE: BRO«M IRREGULAR GRAINS AND BROWNISH MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MUSCOVITE (SERICITE) AS DETRITAL GRAINS THROUBHOUT MATRIX; ISOLATED TOURMALINE CRYSTAL FRAGMENTS. SOME WITH FAINT STRIATIONS 9300-50 SlLTSTONE: ESTIMATED SPHERICITY..69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH THIN FILMS OF OVERGROWTHS AND MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS AND BROWNISH MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; MUSCOVITE (SERICITE) DISTRIBUTED THR0U6H0UT MATRIX AS DETRITAL GRAINS 9350-00 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, SOME GRAINS WITH THIN FILMS OF OVERGROWTH AND MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS AND BROWNISH MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: (XAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MUSCOVITE (SERICITE) DISTRIBUTED THROUBHOUT MATRIX AS DETRITAL GRAINS

9400-40 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, SOME QRAINS WITH THIN FILMS OF OVERGROWTH AND MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN IRREGULAR GRAINS AND BROWNISH MATRIX WHICH FORMS LAMINAE (ULCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLINB PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MUSCOVITE (SERICITE) DISTRIBUTED THROUGHOUT MATRIX AS DETRITAL GRAINS

9700-50 BROWN LIMESTONE WITH SPINES ANO ISOLATEO SUB-ANGULAR QUARTZ GRAINS

SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. GRAINS WITH THIN FILMS OF OVERGROWTH, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ANO PARTIAL REPLACEMENT OF ISOLATED CALCITE RHOMBS AND SPINES IRON OXIDE: AS REDDISH BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTHER MINERAL: ISOLATED PLATES MUSCOVITE 9750-00 ^ SILTSTONE; ESTIMATED SPHERICITY .73 QUARTZ: SU»-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. GRAINS * WITH THIN FILMS OF OVERGROWTH, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS REDDISH BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTMER MINERAL; PLABIOCLASE FELDSPAR 9800-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZEO. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND WITH THIN OVERGROWTH FILMS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS REDDISH BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTHER MINERAL: PLAGIOCLASE FELOSPAR; ISOLATED TOURMALINE CRYSTAL FRAGMENT WITH FAINT STRIATIONS 9850-00 SILTSTONE; ESTIMATED SPHERICITY .69 C^ARTz: SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTH FILMS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS REDDISH BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX OLCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED TOURMALINE CRYSTAL FRAGMENT WITH FAINT STRIATIONS 9900-50 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTH FILMS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED, IRREGULAR BROWN GRAINS ANO BROWN MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE ANO ORAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTHER MINERALS: PLABIOCLASE FELDSPAR PARTIALLY REPLACEO BY QUARTZ; ISOLATED TOURMALINE CRYSTAL FRAQMENTS; ISOLATED GRAINS CHLORITE 9950-60 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SU»-ANQULAR. UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT. SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN OVERGROWTH FILMS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED IRREGULAR BROWN GRAINS ANO BROWN MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL. SERICITE APPEARS AS CHIEF CLAY MINERAL OTHER MI«RALS: PLAGIOCLASE FELDSPAR PARTIALLY REPLACEO BY QUARTZ; ISOLATEO TOURMALINE CRYSTAL FRAGMENTS; ISOLATED GRAINS CHLORITE y&ATir^ i}^^ ^S STEWART DRILLING COMPANY & DAN AULD |l ALWINA KLATTENHOFF LXATION: GAINES COUNTY (694* FNL * 694» Fa OF LAB.. UB. 3. LGE. 295, REAGAN CSL)

¡mmi^ THIN-SEaiQN DESCRIPTIONS 9170-00 BROWN CALCAREOUS SHALE WITH ISOLATED SUB-ANGULAR TO SUB-ROUNDED QUARTZ GRAINS DENSE BROWN LIMESTONE

9200-50 SILTSTONE; ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR, IRREGULARLY SIZED. EVENLY DISTRIBUTED. GRAINS NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS. LARQEST GRAINS MAY BE VERY FINE GRAlNEDSkNO SI ZES OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BLACK AND BROWN IRREGULAR GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; MICROCLINE FELOSPAR 9250-00 DENSE LIGHT BROWN CRYSTALLINE LIMESTONE WITH ISOLATED SUB-ANGULAR QUARTZ GRAINS 9350-00 SlLTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED. UNIFORMLY SIZEO GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BLACK AND BROWN GRAINS AND BROWN MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED ROUNDED ZIRCON CRYSTAL; SERICITE AS A CLAY MINERAL; CHLORITE AS ISOLATEO GRAINS

9450-70 DENSE BROWN CRYSTALLINE LIMESTONE

9810-50 DARK BROWN LIMESTONE WITH SPINES AND OTHER ORGANIC FRAGMENTS, SOME ALGAE

9850-00 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED. UNIFORMLY SIZED. GRAINS NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED TOURMALINE CRYSTAL FRAGMENTS

9900-50 ^ ^ SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT. TOURMALINE INCLUSIONS IN SOME GRAINS, SOME GRAINS WITH THIN FILMS OF OVERGROVTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE 35 IRON OXIDE: AS BROWN ISOLATED IRREGULAR GRAINS ANO BROWN MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLINB PORE SPACE OTHER MINERALS: MICROCLINE FELDSPAR; PLAGIOCLASE FELDSPAR; ISOLATED TOURMALINE CRYSTAL FRAGMENTS 9950-90 BROWN LIMESTONE

SILTSTONE: ESTIMATED SPHERICITY .75 QUARTZ: SUB-ANGULAR. UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS AND THIN FILMS OF OVERGROVTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN ISOLATED IRREGULAR GRAINS AND BROWN MATRIX WHICH FORMS LAMINAE CALCITE: ISOLATED RNOMBS AND IRREGULAR GRAINS MATRIX: GLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED TOURMALINE CRYSTAL FRAQMENTS LOCATION: TERRY COUNTY Í660« S. ANO t980« E. OF SEC. 24, Buc. DO, J. H. GlBSON SURVEY)

^MMUéL THIN-SECTIGN DESCtlPTIQNS 8740-50 ^*!0!íI2**^* c ESTIMATED SPHERICITY .69 VUARTZ: bUB-ANGULAR IRREGULAR GRAINS, LARGER GRAINS SHOW FRACTURING INTO SMALLER ANGULAR GRAINS, SOME GRAINS IN CONTACT WELL DISTRIBUTED THROUGH­ OUT MATRIX OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE CHALCEDONY: REPLACING ISOLATED CALCITE GRAINS IRON OXIDE: ASSOCIATED WITH CEMENT. AND AS DARK IRREGULAR GRANS LALCITE: ISOLATED FRAQMENTS ALMOST COMPLETELY REPLACEO WITH CHALCEDONY MATRIX: CHIEFLY OPAL WITH SMALL AMOUNTS OF IRON OXIDE ANO CLAY OTHER MINERALS: PLAGIOCLASE FELDSPAR 8759-00 DARK BROWN SILTY LIMESTONE (NO SILTSTONE IN CUTTINQS) 8800-50 SlLTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR FRAGMENTAL GRAINS EVENLY DISTRIBUTED, NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE CHALCEDONY: PARTIAL TO TOTAL REPLACEMENT OF ISOLATED CALCITE GRAINS IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACES OTHER MINERAL: PLAGIOCLASE FELDSPAR

8850-00 BROWN FINEGRAINED LIMESTONE COMPOSED OF MICROFOSSIL FRAGMENTS OF TESTS; SOME COVEREO WITH ENCRUSTING BRYZOA. SOME TESTS PARTIALLY SILICIFIED, ISOLATED CALCITE RHOMBS, AND SCATTERED SILT TO CLAY SIZE QUARTZ GRAINS IN A MATRIX OF IRON OXIOE, OPAL ANO CALCIUM CARBONATE FILLING ALL VOIDS. ALTERATION OF TESTS PRESENTS IDENTIFICATION. SOME VEINS OF CALCITE M.TERING TO CHALCEDONY.

8900—50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR UNIFORMLY SIZEO GRAINS. WELL DISTRIBUTED. NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: SCATTERED IRREGULAR BLACK GRAINS AND AS BROWNISH MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

8950—00 BROWN FINE GRAINED LIMESTONE CONTAINING FRAGMENTS OF MICROFOSSIL TESTS. RADIOLARIA AND ISOLATED QUARTZ SILT GRAINS IN A MATRIX OF IRON OXIOE AND CALCIUM CARBONATE (NO TRUE SlLTSTONE IN CUTTINGS AT THIS INTERVAL)

9000-90 BROWN FINE GRAINED LIMESTONE CONTAINING CALCIUM CARBONATE FRAGMENTS, MICROFOSSIL TESTS FRAGMENTS. AND RADIOLARIA WHICH ARE PARTIALLY SILICIFIED 37 9050-00 ^*k7.^'*^' c ESTIMATED SPHBRICITY .69 QUARTZ: SUB-ANGULAR. UNIFORMLY SIZED GRAINS. WELL DISTRIBUTED. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS O^AL: CMIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED RAGGED GRAINS MANGANESE DIOXIDE 9100-50 BROWN FINE GRAINED LIMESTONE 9150-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR UNIFORMLY SIZED GRAINS, WELL DISTRIBUTED, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED RAGGED GRAINS MANGANESE DIOXIDE 9200-50 BROWN LIMESTONE COMPOSED OF ORGANIC FRAGMENTS AND SPINES. PARTIALLY REPLACED BY OPAL; IRON OXIDE CHIEFLY AS A MATRIX WITH CALCIUM CARBONATE; ISOLATED SCATTERED SILT SIZEO QUARTZ GRAINS 9730-50 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

9750-00 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN MATRIX AND DARKER BROWN PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

9800-50 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN MATRIX AND DARKER BROV/N PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR 9850—00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWN MATRIX AND DARKER BROWN PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLABIOCLASE FELOSPAR 9900-50 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED QRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE 9950—10 000 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANQULAR, UNIFORMLY SIZED GRAINS, NOT IN CONTACT OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: MICROCLINE FELOSPAR í'9:ti.^ ^' ^' ^ELTiNG |1 SANOIDGE LOCATION: DAWSON COUNTY (1980» FROM N 4 W OF SEC. SEC. lio. BLK. M, EL 4 RR SURVEY)

*^^^^ TMIIJ-STCTIOJ DESCRIPTIONS 8195-97 WILTSTONE: ESTIMATED SPHERICITY .61 QUARTZ: ANGULAR TO SUB-ANOULAR, LARGEST GRAINS FOUR DIAMETERS OF SMALLEST GRAINS. NOT IN CONTACT (MATRIX BETWEEN GRAINS) GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE; IRREGULAR ISOLATED GRAINS IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX (HEMATITE) SENDINQ IRREGULAR PROJECTIONS OUT INTO MATRIX WHICH FORM OARK LAMINAE JJATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR AS ISOLATED GRAINS 8197-99 SijJSTONE; ESTIMATED SPHERICITY .63 QUARTZ: ANGULAR TO SUB-ANGULAR AS ABOVE EXCEPT FOR GENERAL INCREASE IN GRAIN SIZE. NOT EXCEEDING THE SIZE OF THE LARGER GRAiNS OF 8195-97 AND BECOMING MORE UNIFORM OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE: IRREGULAR ISOLATED GRAINS, SOME GRAINS PARTIALLY REPLACEO WITH SILICA IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX (HEMATITE) SENDINQ IRRKGUI.AR PROJECTIONS OUT INTO MATRIX WHICH FORM OARK LAMINAE MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8199-201 SILTSTONE; ESTIMATED SPHERICITY .63 QUARTZ: ANGULAR TO SUB-ANGULAR. UNIFORM GRAIN SIZES, NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX (HEMATITE) SENDINQ IRREGULAR PROJECTIONS OUT INTO MATRIX WHICH FORM DARK LAMINAE CALCITE; IRREGULAR ISOLATED GRAINS. SOME GRAINS PARTIALLY REPLACEO WITH SILICA MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8201-04 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR TO SUB-ANGULAR, UNIFORM GRAIN SIZES, EVENLY DISTRIBUTED OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT [RON OXIDE: IRREGULAR BLACK GRAINS ANO IRREGULAR ALTERED ISOLATED GRAINS. REDDISH BROWN HEMATITE CALCITE: IRREGULAR ISOLATED GRAINS MA»RIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR AS ISOLATED GRAINS 8204-06 SILTSTONE: ESTIMATED SPHERICITY .68 QUARTZ: SUB-ANGULAR GRAIN SIZES, EVENLY DISTRIBUTED, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS ANO IRREGULAR ALTERED ISOLATED GRAINS. REDDISH BROWN HEMATITE CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; RUTILE AS ISOLATED CRYSTAL FRAGMENTS 8206-08 ^ SlLTSTONE: ESTIMATED SPHERICITY .65 guARTz: SUB-ANGULAR TO ANGULAR, EVENLY DISTRIBUTED, GRAINS NOT IN CONTACT UPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS. ISOLATED GRAINS REDDISH BROWN HEMATITE ANO AS A COATING ON SOME QUARTZ GRAINS CALCITE; IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; TOURMALINE AS ISOLATED PLEOCHROIC LONG SLENDER CRYSTALS 8208-10 SILTSTONE: ESTIMATED SPHERICITY .68 QUARTZ: SUB-ANGULAR TO EVENLY DISTRIBUTED GRAINS, UNIFORM IN SIZE OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS, ISOLATED GRAINS REDDISH BROWN HEMATITE AND AS A COATING ON SOME QUAPTZ GRAINS CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER I^INERSL: PLAGIOCLASE FELDSPAR 8210-12 SlLTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, UNIFORM IN SIZE OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS, ISOLATED GRAINS REDDISH BROWN HEMATITE AS A COATING ON SOME QUARTZ GRAINS CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ZIRCON AS A SUB-ANGULAR FRAGMENT 8212-14 SILTSTONE: ESTIMATED SPHERICITY .63 OUARTZ: SU»'ANGULAR GRAINS. EVENLY DISTRIBUTED. NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS, ISOLATED GRAINS REDDISH BROWN HEMATITE AND AS A COATING ON SOME QUARTZ GRAINS CALCITE; IRREGULAR ISOLATED GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ZIRCON AND RUTILE AS ISOLATED FRAGMENTS 8214-16 SILTSTONE: ESTIMATED SPHERICITY .62 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED. NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS. ISOLATED GRAINS REDDISH BROWN HEMATITE AND AS A COATING ON SOME QUARTZ GRAINS CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8216-18 SILTSTONE: ESTIMATED SPHERICITY .68 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED, NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS, ISOLATED GRAINS REDDISH BROWN HEMATITE ANO AS A COATING ON SOME QUARTZ GRAINS CALCITE; IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ZIRCON AS LIGKT BROWN CRYSTAL FRAGMENTS

/ 41 8218-20 ^'JJ*™"^' _ ESTIMATED SPHERICITY .61 OUARTZ: Sue-ANGULAR GRAINS, EVENLY DISTRIBUTED. NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS. ISOLATED GRAINS. REDDISH BROWN HEMATITE CALCITE: IRREGU.AR ISOLATED GRAINS ¡JATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8226-28 SILTSTONE; ESTIMATED SPHERICITY .59 OüARTz: SUB-ANGULAR GRAINS. EVENLY DISTRIBUTED. NOT IN CONTACT • *"^/% ^^•^'^y *S CEMENT ASSOCIATED WITH IRON OXIOE. SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS. ISOLATED GRAINS REDDISH BROWN HEMATITE AND AS A COATING ON SOME QUARTZ GRAINS CALCITE; IRREGULAR ISOLATED GRAINS MATRIX; CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; GARNET AS PARTIALLY ROUNDED, AMBER COLOREO ISOLATED GRAINS 8234-36 SILTSTONE; ESTIMATED SPHERICITY .61 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. EVENLY DISTRIBUTED, NOT IN CONTACT, OVERGROWTHS ON SOME GRAINS, GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX, AND ISOLATED FRAGMENTS OF ALTERED HEMATITE CALCITE: IRREGULAR ISOLATED GRAINS. PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: RUTILE INCLUSIONS IN QUARTZ; PLAGIOCLASE FELDSPAR 8228-30 SILTSTONE; ESTIMATED SPHERICITY .63 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED. NOT IN CONTACT OPAL: CNIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE: IRREGULAR ISOLATED GRAINS, PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX, AND ISOLATEO FRAGMENTS OF ALTERED HEMATITE MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: C^HLORITE AS ISOLATED, IRREGULAR GRAINS, ISOLATED GRAINS PLAGIOCLASE FELDSPAR

8230-32 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR GRAINS, EVENLY DISTRIBUTED, NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX, AND ISOLATED FRAGMENTS OF ALTERED HEMATITE CALCITE: IRREGULAR ISOLATED GRAINS. PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELOSPAR; PLAGIOCLASE FELDSPAR

8236-38 SILTSTONE: ESTIMTTED SPHERICITY .66 QUARTZ: SUB-ANGULAR, WELL DISTRIBUTED GRAINS WITH SOME OVERGROWTH FILMS OPAL: CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX. ANO ISOLATED FRAGMENTS OF ALTERED NEMATITE CALCITE: IRREGULAR ISOLATED GRAINS, PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR AS ISOLATLO GRAINS 8238-40 SIU-STONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. WELL DISTRIBUTED GRAINS. WITH SOME OVERGROWTH FILMS Y'AL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT ¡RON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX. AND ISOLATED FRAGMENTS OF ALTERED HEMATITE CALCITE; IRREGULAR ISOLATED GRAINS, PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: RUTILE INCLUSIONS IN QUARTZ; PLAGIOCLASE FELOSPAR AS ISOLATEO GRAINS 8240-41 SlLTSTONE: ESTIMATED SPHERICITY .75 QUARTZ: SUB-ANGULAR, WELL DISTRIBUTED. UNIFORM GRAINS WITH OVERGROWTH FILM AND MICROLITIC INCLUSIONS OPAL; CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX, ANO ISOLATED FRAGMENTS OF ALTERED HEMATITE CALCITE: IRREGULAR ISOLATED GRAINS, PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX; CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8332-34 SILTSTONE: ESTIMATED SPHERICITY .70 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT (MATRIX BETWEEN GRAINS) THIN FILM OF OVERGROWTH ON SOME GRAINS; GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL; CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SEKING IRREGULAR PROJECTIONS OUT INTO MATRIX MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

8334—36 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT (MATRIX BETWEEN GRAINS) THIN FILM OF OVERGROWTH ON SOME GRAINS; GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

8336-38 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT (MATRIX BETWEEN GRAINS) THIN FILM OF OVERGROWTH OVER SOME GRAiNS; GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CNIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) 43 IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE 8338-40 SILTSTONE; ESTIMATED SPHERICITY .71 WUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT. THIN FILM OF OVERGROWTHS ON SOME GRAINS OPAL: CHEEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT LALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO BY SILICA (SOME GRAINS) IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE QTHER MINERAL: RUTILE INCLUSIONS IN QUARTZ (SOME GRAINS) 8340-42 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN FILM OF OVERGROWTHS ON SOME GRAINS OPAL: (^IEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED RUTILE CRYSTAL FRAGMENTS 8342-44 SILTSTONE; ESTIMATED SPHERICITY .72 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT, THIN FILM OF OVERGROWTHS ON SOME GRAINS OPAL: OIIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOHE REPLACEMENT IRON OXIDE: IRREGÍX.AR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE 8344-46 SILTSTONE: ESTIMATED SPHERICITY .68 QUARTZ: ANGULAR GRAINS, UNIFOIM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL; CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED CRYSTAL FRAGMENTS OF RUTILE

8346—48 SILTSTONE; ESTIMATED SPHERICITY .65 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: MICROCLINE FELDSPAR 8348-50 ^ ^'rJ.ÍIS!^' ._ ESTIMATED SPHERICITY .63 VUANTz. ANGULAR GRAINS. UNIFORM IN SIZE. NOT IN CONTACT, THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON UXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED SRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED IRREGULAR GRAIN CHLORITE 8360-52 SILTSTONE: ESTIMATBD SPHERICITY .65 üUARTz: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8352-54 SlLTSTONE: ESTIMATED SPHERICITY .64 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

8354-56 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT, THIN ovERQROirTHs ON SOME GRAINS, GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT ¡RON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED IRREGULAR FRAGMENTS OF CHLORITE GRAINS

8356-58 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

8358-60 re SILTSTONE* ESTIMATED SPHERICITY .67 QUARTZ:* ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAlN MICROLITIC INCLUSIONS 834d-«) ^ ^'n7.?I2!^* A-..- ^ ESTIMATED SPHERICITY .63 ^ í L ANGULAR GRAINS. UNIFORM IN SIZE. NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAIN MICROLITIC INCLUSIONS itíh'cwTÍ!^'^*"! ^* COIENT ASSOCIATED WITH IRON OXIOE. SHOWS SOME REPLACEMENT IRON UXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED IRREGULAR GRAIN CHLORITE 8350-52 SILTSTONE: ESTIMATBD SPHERICITY .65 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT, THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS ANO BGOWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8352-54 SILTSTONE: ESTIMATED SPHERICITY .64 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE. NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8354-56 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT, THIN OVERQROWTHS ON SOME GRAINS. GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED IRREGULAR FRAGMENTS OF CHLORITE GRAINS

8356-58 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ; ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

8358-60 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT, THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAlN MICROLITIC INCLUSIONS 45 OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON CXI DE: IRREGULAR BLACK GRAINS AND BROWNISM COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELDSPAR; PLAGIOCLASE FELDSPAR 8360-62 SILTSTONE: ESTIMATED SPHERICITY .65 (^ARTz: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS, GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRANS) MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SBM^CE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8362-64 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. THIN OVERGROWTHS ON SOME GRAINS. GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT, ASSOCIATED WITH IRON OXIDE SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS AND BGOWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAMS) MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; MICROCLINE FELDSPAR

8364-65 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. WITH THIN OVER­ GROWTHS ON SOME GRAINS, GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWNISH COLOREO MATRIX SENDING IRREGULAR PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS PARTIALLY REPLACEO WITH SILICA (SOME GRAINS) MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS; PLAGIOCLASE FELOSPAR; MICROCLINE FELBSPAR 7985—00 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ:* SUB-ANOULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. SOME GRAINS WITH MICROLITIC INCLUSIONS, LARGEST GRAINS SIX DIAMETERS SMALLEST GRAINS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED DARK GRAINS AND REDDISH BROWN MATRIX WHICH SENOS PROJECTIONS OUT INTO MATRIX AND FORMS LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS; PLAGIOCLASE FELDSPAR; ISOLATED PLATES MUSCOVITE

^^^^^^SiLTSTONE» ESTIMATED SPHERICITY .t>9 OUARTZ:* SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS. NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED IRREGULAR BLACK AND BROWN GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND RHOMBS 46 MATRIX; CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR SHOWINS PARTIAL REPLACEMENT BY QUARTZ; ISOLATED TOURÍIALIHE CRYSTAL FRAGMENTS WITH STRIATIONS; ISOLATEO PLATES MUSCOVITE 8050-00 SILTSTONE: ESTIMATED >HE«ICITY .69 í^ARTz: SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZEO GRAIN¿, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS, SOME GRAINS SHCA STRAINING OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH I NON OXIDE IRON OXIDE: ISOLATED IRREGULAR BLACK AND BROWN GRAINS ANO BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS ANO RHOMBS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETI.Y FILLING PORE SPACE OTHER MINERALS: HLAGIOCLASE FELDSPAR; ISOLATED TOURMALINE CRYSTAL FRAGMENTS 8100-90 SILTSTONE: ESTIMATED SPHERICITY .66 QUARTZ: SU»-ANGULAR, EVENLY DISTRIBUTED. UNIFORMLY SIZED GRAINS, NOT IN CONTACT. SOME GRAINS WITH MICROLITIC INCLUSIONS, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED IRREGULAR BLACK ANO BROWN GRAINS ANO BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTMER MINERALS: PLAGIOCLASE FELOSPAR; ISOLATED GRAINS CHLORITE 8190-95 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED. UNIFORMLY SIZEO GIUINS. NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS. SOME «RAlNS SHOW STRAINING OPAL: AS cmcNT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED IRREGULAR BLACK AND BROWN GIUINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: (XAV. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED IRREGULAR BLACK GRAINS MANGANESE DIOXIDC; ISOLATED PLATES MUSCOVITE; ISOLATED GRAINS CHLORITE, WCLL-ROUNDED TOURMALINE CRYSTAL 8240-50 SILTSTONE: ESTIMATED SPHERICITY .C7 QUARTZ: SU»-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS, LARGEST GRAINS FOUR DIAMETERS OF «ALLEST GRAINS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIOE IRON OXIDE: BLACK AMO BROWN IRREGULAR GRAINS AND BROWNISH MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR PARTIALLY REPLACEO BY QUARTZ; ISOLATED PLATES MUSCOVITE

SILTSTONE: ESTIMATED SPHERICITY .69 OuARTz: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, SOME GRAINS WITM MICROLITIC INCLUSIONS, LARGEST GRAINS FOUR DIAMETERS OF «lALLEST GRAINS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED IRREGULAR BROWN GRAINS ANO BROWNISH MATRIX CALCITE; ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OcMCR MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED WELL-W)RN TOURMALINE CRYSTAL FRABMENTS; ISOLATED PLATES MUSCGVITE 47 8300-35 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS, NOT IN CONTACT, SOME QRAINS WITH MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED IRREGULAR BROWN GRAINS AND BROWNISH MATRIX FORMING LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; IRREGULAR ISOLATED GRAINS CHLORITE 8384-00 SILTSTONE: ESTIMATED SPHERICITY .66 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED IRREGULAR BROWN GRAINS AND BROWNISH MATRIX FORMING LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED IRREGULAR GRAINS MANGANESE DIOXIDE; ISOLATED. WELL-WORN TOURMALINE CRYSTAL FRAGMENTS 8400-90 SILTSTONE: ESTIMATED SPHERICITY .69 QüAPJzz SUB-ANGULAR. EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS, NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED IRREGULAR BROWN GRAINS AND BROWNISH MATRIX FORMING LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: SHORT FRAGMENT TOURMALINE CRYSTAL WITH STRIATIONS; ISOUTEO PLATES MUSCOVITE

8450-70 SILTSTONE: ESTIMATED SPHERICITY. 73 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS. NOT IN CONTACT, SOME GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED IRREGULAR BROWN GRAINS ANO BROWNISH MATRIX MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE CÍTHER MINERALS: ISOLATED TOURMALINE CRYSTAL FRAGMENT WITH STRIATIONS; ISOLATED PLATES MUSCOVITE MELL: AMERADA §1 NW WILLARO LOCATION; TERRY COUNTY (SEC. 6, Buc. C-37. PSL. 660» FROM NL 4 W.0F SEC.)

ÍMSUÉL THIN-SECTIOM DESCRIPTIONS 7800-90 DENSE BROWN LIMESTONE WITH ISOLATED QUARTZ GRAINS

7890-00 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ; SUB-ANQULAR, UNIFORMLY SIZED, WELL DISTRIBUTED GRAINS, NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWNISH MATRIX AND IRREGULAR BLACK GRANS CALCITE: ISOUTED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED PLATES MUSCOVITE; PLAGIOCLASE FELOSPAR

7900-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, WELL DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; BROWNISH MATRIX ANO IRREGULAR BLACK GRAINS CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: (XAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED PLATES MUSCOVITE

7950—8000 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, WELL DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWNISH MATRIX AND IRREGULAR BLACK GRAINS CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED PLATES MUSCOVITE

8000-90 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZEO, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED GRAINS ANO MATRIX BROWNISH CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED PLATES MUSCOVITE; ISOLATED

FRAGMENTS OF TOURMALINE CRYSTAL WITH STRIATIONS

«««»,. „TONE. ESTIMATED SPHERIC.TY .68 QUARTZ:* SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BLACK GRAINS AND BROWNISH MATRIX CALC I TE: 1 SOLATED IRREGULAR GRAl NS MATRIX; CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; ISOLATED PLATES MUSCOVITE; ISOLATED WELL-ROUNDED TOURMALINE CRYSTALS 49 8100-90 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR. UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED BLACK GRAINS AND BROWNISH MATRIX CALCITE: ISOLATED IRREGULAR GRAINS AND AS REPLACEMENT OF SPINES AND ISOLATED RHOMBS MATRIX: CLAY, IRON OXIDE, OPAL AND SMALL AMOUNT CALCIUM CARBONATE OTICR MINERALS: PLAGIOCLASE FELDSPAR; WELL-ROUNDED FRAGMENT OF TOURMALINE CRYSTAL

8150-00 SILTSTONE; ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED QRAINS. NOT IN CONTACT. GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED BLACK GRAINS ANO BROWNISH MATRIX CALCITE; AS ISOLATED GRAINS ANO RHOMBS MATIIIX: CLAY, IRON OXIDE, OPAL AND SMALL AMOUNT CALCIUM CARBONATE OTHER MINERALS: PLAGIOCLASE FELDSPAR PARTIALLY REPLACEO BY QUARTZ; TOURMALINE CRYSTAL FRAGMENT WITH STRIATIONS; ISOLATED PLATES MUSCOVITE 8200-90 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, GRAINS WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BLACK GRANNS AND BROWNISH MATRIX OLCITE: AS ISOLATED GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL ANO SMALL AMOUNT CALCIUM CARBONATE OTHER MINERALS: ISOLATED GRAIN CHLORITE; PLAGIOCLASE FELDSPAR PARTIALLY REPLACED BY QUARTZ; ISOLATED. WORN TOURMALINE CRYSTAL FRAGMENT WITH FAINT STRIATIONS

8250-00 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS WITH MICROLITIC INCLUSIONS. GRAINS DO NOT CONTACT. SOME QRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BLACK GRAINS AND BROWNISH MATRIX CALCITE: AS ISOLATED GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE, OPAL ANO MALL AMOUNT CALCIUM CARBONATE OTHER MINERALS: ISOLATED PLATES MUSCOVITE; ISOLATED RUTILE CRYSTAL FRAGMENTS; ALTERED PLAGIOCLASE FELDSPAR

8300-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS WITH MICROLITIC INCLUSIONS, GRAINS NOT IN CONTACT, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASGOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED BLACK GRAINS ANO BROWNISH MARRIX CALCITE; AS ISOLATED GRAINS AND RHOMBS MATRIX: CLAY, IRON OXIDE, OPAL AND SMALL AMOUNT CALCIUM CARBONATE OTHER MINERALS: PSOLATEO GRAINS CHLORITE; ISOLATED ZIRCON CRYSTAL 8350—00 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SU»-ANGULAR. EVENLY DISTRIBUTED GRAINS WITH MICROLITIC INCLUSIONS, GRAINS NOT IN CONTACT, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BLACK GRAINS AND BROIRIISH MATRIX CALCITE: AS ISOLATED GRAINS ANO RHOMBS 50 MATRIXS CLAY. IRON OXIDE, OPAL ANO SMALL AMOUNT CALCIUM CARBONATE OTMER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR; MICROCLINE FELDSPAR 8400-90 SILTSTONE: EH-IMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS WITH MICROLITIC INCLUSIONS. GRAINS NOT IN CONTACT, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED BLACK GRAINS ANO BROWNISH MATRIX CALCITE: AS ISOLATED GRAINS ANO RHOMBS MATRIX; CLAY, IRON OXIDE, OPAL ANO SMALL AMOUNT CALCIUM CARBONATE OTHER MINERALS: ISOLATED GRAINS CHLORITE; ISOLATED FRAGMENTS TOURMALINE CRYSTAL FRAGMENTS WITH STRIATIONS 8450-70 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS WITH MICROLITIC INCLUSIONS, GRAINS NOT IN CONTACT, SOME GRAINS SHOW STRAINING OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWNISH MATRIX AND LAMINAE CALCITE: AS ISOLATED GRAINS AND RHOMBS MATRIX; CLAY, IRON OXIDE ANO OPAL AND SMALL AMOUNT CALCIIW CARBONATE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR WELL: ClTIES PRODUCTION CORPORATION, LEVERETT "B" NO. L LOCATION: DAWSON COUNTY (SEC. 3. BLK. 4. D. L. CUNNINGHAM SURVEY, 1980« FROM SL 4 WL OF SEC.)

IhMUáL THIN-SECTION DESCRIPTIONS 7970-00 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED, UNIFORMLY SIZED GRAINS. NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: CNIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; IRREGULAR OARK BROWN GRAINS ANO MATRIX CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTMER MINERALS: ISOLATED CHLORITE, PLAGIOCLASE FELDSPAR GRAINS; ISOLATED TOURMALINE CRYSTAL FRAGMENTS WITH FRACWJRED ENDS ANO WELL MARKED STRIATIONS 8000-90 SILTSTONE: ESTIMATEB SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZED, GRAINS NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: OIIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SRACE OTHER MINERAL; PLAGIOCLASE FELDSPAR

8050«KX) SILTSTONE; ESTIMATED SPHERICITY .67 QUARTZ; SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZEO QRAINS. NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: ISOLATED RHOMBS ANO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: CHLORITE AS AN ISOLATED GRAIN; PLAGIOCLASE FELDSPAR

8100-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ; SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZED, GRAINS NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL; CHEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR DARK GRAINS AND BROWN MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR; MICRO­ CLINE FELDSPAR AND ISOLATED RUTILE CRYSTAL WITH INCLUSIONS

8150—00 "^SlLTSTONE* ESTIMATED SPHERICITY .71 QUARTZ:* SUB-ANGULAR, UNIFORMLY SIZED GRAINS. NOT IN CONTACT, SOME GRAINS SHOW EVIOENCE OF STRAINING ANO CONTAlN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR DARK BROWN GRAINS ANO MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; MUSCOVITE AS ISOLATED PLATES 8200-50 ONE FRAGMENT TAN OOLITIC LIMESTONE. OOLITIC STRUCTURE PARTIALLY DESTROYED BY REPLACEMENT

SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED GRAINS, NOT IN CONTACT. SOME GRAINS SHOW EVIOENCE OF STRAINING AND CONTALN MICROLITIC INCLUSIONS OPALI CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR ANO ISOLATED PLATES MUSCOVITE 8250-00 DENSE BROWN LIMESTONE WITH ISOLATEO ANGULAR QUARTZ GRAINS

SILTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZEO, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELOSPAR; ISOLATED GRAINS CHLORITE 8300-50 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT OPAU AS CEMENT ASSOCIATED WITH IRON OXIDE CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELBSPAR; ISOLATED GRAINS CHLORITE

8350-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR, DARK BROWN GRAINS AND DARK BROWN MATRIX FORMING LAMINAE CALCITE: ISOLATED IRREGULAR GRAINS AND RHOMBS MATRIX: CLAY. IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHIR MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED GRAINS CHLORITE

8400—50 SILTSTONE; ESTIMATED SPHERICITY .69 OuARTzr* SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZEO GRAINS. NOT IN CONTACT, SOME GRAINS HAVE THIN FILMS OF OVERBROWTH ANO CONTAlN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR ISOLATED BROWN GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATEO GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTMER MINERALS: ISOLATED WELL ROUNDED CRYSTAL FRAGMENT TOURMALINE; PLAGIOCLASE FELOSPAR; ISOLATEO IRREGULAR GRAINS CHLORITE

8450—70 SlLTSTONE* ESTIMATED SPHERICITY .67 QUARTZ:' SUB-ANGULAR, EVENLY DISTRIBUTED. UNIFORMLY SIZEO GRAINS. NOT IN CONTACT, SOME GRAINS HAVE THIN FILM OF OVERGROWTHS ANO CONTAlN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRONOKIOE IRON OXIDE: IRREGULAR ISOLATED BROWN GRAINS AND BROWN MATRIX 53 CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS; PLAGIOCLASE FELDSPAR AND ISOLATED GRAINS CHLORITE

8690-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR GRAINS, SOME WITH THIN FILMS OF OVERGROWTH, SOME GRAINS ALMOST IN CONTACT WITH DARK COATING OF IRON OXIDE, GRAINS CONTAlN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE, AND ALSO AS REPLACEMENT OF AN ISOLATED SPINE IRON OXIDE: AS ISOLATED BLACK GRAINS AND BROWNISH MATRIX CALCITE; ISOLATED IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR, ISOLATED PLATES MUSCOVITE 8700-50 SILTSTONE: ÍÍSTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED. SIZES VARY. THE LARGEST GRAINS AS MANY AS FOUR DIAMETERS THE SMALLEST GRAINS; GRAINS CONTALN MICROLITIC INCLUSIONS, SOME GRAINS WITH OVERGROWTHS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED DARK BROWN GRAINS ANO BROWNISH COLOREO MATRIX OLCITE; ISOLATED IRREGULAR GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR;MÍCROCLINE FELDSPAR

8750—00 SlLTSTONE; ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANQULAR. EVENLY DISTRIBUTED GRAINS. VARYING IN SIZE AS MUCH AS FOUR DIAMETERS» NOT IN CONTACT, CONTALN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED DARK BROWN GRAINS ANO BROWNISH COLOREO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED, RAGGED PLATES MUSCOVITE; PLAGIOCLASE FELDSPAR

8800-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, VARYING IN SIZE AS MUCH AS FOUR DIAMETERS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL; AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED DARK BROWN GRAINS AND BROWNISH COLOREO MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE ANO PLAGIOCLASE FELDSPAR; ISOLATED PLATES MUSCOVITE

8850—00 ^^^SiLTSTONE* ESTIMATED SPHERICITY .71 QUARTZ:' SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS, VARYING IN SIZE AS MUCH AS FOUR DIAMETERS. NOT IN CONTACT. CONTAlN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS ISOLATED DARK BROWN GRAINS ANO BROWNISH COLOREO MATRIX CALCITE; ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLIMQ PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; ISOLATED PLATES MUSCOVITE WELL: DELHI #1 OIL DEVELOPMENT COMPANY LOCATION: GAINES COUNTY (660* FROM N 4 W OF SEC. , SEC. 27, BLK. G. C 4 M SURVEY)

mSSiíÉL THIN-SECTION DESCRIPTIONS 8715-50 BROWN LIMESTONE WITH ISOLATEO ANGULAR QUARTZ GRAINS. SOME OPAL DISSEMINATED THROUQHOUT, SOME CHALCEDONY REPLACING CALCITE IN FRACTURE

8750-00 BROWN LIMESTONE WITH ORGANIC FRAGMENTS ANO ISOLATED ANGULAR QUARTZ GRAINS WITH OVERGROWTH FILMS, OPAL WELL DISSEMINATED THROUGHOUT LIME FRAOMENTS

8800-50 BROWN LIMESTONE WITH ORGANIC SPINES AND RADIOLARIA REPLACEO WITH CALCITE; OPAL REPLACEMENT IN SOME RADIOLARIA CENTERS, ISOLATEO ANGULAR QUARTZ GRAINS. SOME SPINES PARTIALLY SILICIFIED

SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR GRAINS EVENLY DISTRIBUTED. UNIFORMLY SIZEO, NOT IN CONTACT OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE. IRREGULAR BLACK GRAINS DISSEMINATED THROUQHOUT MATRIX CALCITE; IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SRACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

8850-00 BROWN LIMESTONE WITH SPINES ANO RADIOLARIA AND ISOLATEO ANGULAR QUARTZ GRAINS. IRREGULAR PATCHES HEMATITE THROUQHOUT MATRIX, SOME OPAL REPLACEMENT ON ISOLATED FRAGMENTS AND SPINES

SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: WIOELY SCATTERED, SUB-ANGULAR GRAINS, NOT IN CONTACT, SOME GRAINS WITH THIN FILM OF OVERGROWTHS OPAL: DISTRIBUTED THROUGHOUT MATRIX, ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR REDDISH BROWN ISGLATEO GRAINS HEMATITE, IRREGULAR BLACK GRAINS DISSEMINATED THROUGHOUT MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8900-50 BROWN LIMESTONE WITH SPINES AND RADIOLARIA AND ISOLATED ANGULAR QUARTZ QRAiNS, IRREGW.AR PATCHES HEMATITE THROUGHOUT MATRIX, SOME OPAL REPLACEMENT ON ISOLATED FRAGMENTS AND SPINES, SOME CHALCEDONY ON EOGE OF FRAGMENT WHICH SUQGEST FILLING OF A FRACTURE SILTSTONE; ESTIMATED SPHERICITY .65 QUARTZ:* WIOELY SCATTERED. SUB-ANGULAR GRAINS. NOT IN CONTACT. SOME GRAINS WITH THIN FILM OF OVERGROWTHS OPAL; DISTRIBUTED THROUGHOUT MATRIX. ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE, IRREGULAR BLACK GRAINS DISSEMINATED THROUQHOUT MATRIX CALCITE; IRRUULAR ISOLATED GRAINS 55 MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE 8950-00 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: WIOELY SCATTERED, SUB-ANGULAR GRAINS. NOT IN CONTACT. SOME GRAINS WITH THIN FILM OF OVERGROWTHS OPAL: DISTRIBUTED THROUGHOUT MATRIX, ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE, IRREGULAR BLACK GRAINS DISSEMINATED THROUGHOUT MATRIX CALCITE; IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 9000-90 ^'JrJ.*^**^^ ui ESTIMATED SPHERICITY .69 QUARTZ: WIOELY SCATTERED. SUB-ANGULAR GRAINS, NOT IN CONTACT. SOME GRAINS WITH THIN FILM OF OVERGROWTHS OPAL: TOTALLY REPUCING SOME SPINES AND ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE: SCATTERED ISOLATED GRAINS SHOWING SOME SILICIOUS REPLACEMENT MATIIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTMER MINERAL: PLAGIOCLASE FELDSPAR 9050-00 BROWN LIMESTONE WITH ORGANIC FRAGMENTS AND SPINES. SOME CHALCEDONIC REPLACEMENT OF FRAGMENTS ANO SOME SPINES PARTIALLY SILICIFIED.

SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORMLY SIZEO GRAINS, NOT IN CONTACT, SOME GRAINS SHOW THIN FILM OF OVERBROVTH OPAL: CHIEFLY ASSOCIATED WITH IRON OXIDE AS MATRIX BUT ALSO IN PARTIAL REPLACEMENT OF ORGANIC CALCAREOUS FRAGMENTS IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE; ISOLATED ORGANIC FRAGMENTS AND ISOLATED IRREGULAR GRAINS MATRIX: (XAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

9100-50 BROWN LIMESTONE CONTAINS ABUNDANT AMOUNT OF SPINES WHICH ARE PARTIALLY SILICIFIED

SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. CONTAINING MICROLITIC INCLUSIONS; ONE SMALL AGGREGATE MASS OF VERY FINE SILT SIZE GRAINS WHICH MAY REPRESENT THE DISINTEGRATION OF A LARGER QUARTZ GRAIN OPAL: CHIEFLY ASSOCIATED WITH IRON OXIDE AS MATRIX BUT ALSO AS PARTIAL REPLACEMENT OF ORGANIC CALCAREOUS FRAGMENTS IRON OXIDE; IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATED ORGANIC FRAGMENTS ANO ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

9150—00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED. UNIFORM GRAINS, NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY ASSOCIATED WITH IRON OXIDE AS MATRIX BUT ALSO IN PARTIAL REPLACEMENT OF ORGANIC CALCAREOUS FRAGMENTS IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX 56 CALCITE; ISOLATED ORGANIC FRAGMENTS AND ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE 9200-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED. UNIFORM GRAINS, NOT IN CONTACT. CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY ASSOCIATED WITH IRON OXIDE AS MATRIX BUT ALSO IN PARTIAL REPLACEMENT OF ORGANIC CALCAREOUS FRAQMENTS IRON OXIDE; IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE; ISOLATED ORGANIC FRAGMENTS AND ISOLATED IRREGULAR GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE 9250-00 SILTSTONE: ESTIMATED SPHERICITY .69 (^ARTz: SUB-ANGULAR, EVENLY DISTRIBUTED, UNIFORM GRAINS. NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY ASSOCIATED WITH IRON OXIDE AS MATRIX BUT ALSO IN PARTIAL REPLACEMENT OF ORGANIC CALCAREOUS FRAGMENTS IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK QRAINS FMÍCH FORM PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATEO ORGANIC FRAGMENTS AND ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

9300-50 SILTSTONE; ESTIMATED SPHERICITY .65 QUARTZ; SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE; ALSO PRESENT AS A PARTIAL REPLACEMENT OF ISOLATED SPINES IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE; IRREGULAR ISOLATED GRAINS AND ORGANIC FRAGMENTS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

9350^)0 ^^^SILTSTONE; ESTIMATED SPHERICITY .65 QUARTZ:' SUB-ANGULAR, GNIFORMLY SIZEO, EVENLY DISTRIBUTED. GRAINS NOT IN CONTACT. CONTAINING MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIÍTED WITH IRON OXIDE; ALSO PRESENT AS A PARTIAL REPLACEMENT OF ISOLATED GRAINS IRON OXIDE: IRREGULAR REDDISH BROWN ISOLATED GRAINS HEMATITE AND IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND ORGANIC FRAGMENTS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

9400-50 ^'Sííízr SUB-ANGULAR, UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAINING MICROLITIC »NCLUSIONS .orsrMT AS A OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, ALSO PRESENT AS A PARTIAL REPLACEMENT OF ISOLATED SPINES ^„^,^. MF-ATITC AMD IRREGULAR IRON OXIDE: IRREGULAR REDOISH BROWN ISOLATED GRAINS HEMATITE ANO IRREGULAR BLACK GRAINS WHICH FORM PROJECTIONS OUT INTO MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND ORGANIC FRAGMENTS OTHER MINERALS: PLAGIOCLASE FELDSPAR 9770-00 _ SILTSTONE:NOT PRESENT IN CUTTINGS 57 BROWN LIMESTONE WITH FOSSIL FRAGMENTS OF CALCITE AND RADIOLARIA OF CALCITE IN MATRIX OF CLAY. IRON OXIDE AND CALCIUM CARBONATE IRON OXIDE IS ABUNOANT AS REDDISH BROWN HEMATITE 9800-50 SILTSTONE NOT PRESENT IN CUTTINGS

BROWN LIMESTONE WITH ORGANIC FRAQMENTS OF CALCITE ANO RADIOLARIA OF CALCITE IN MATRIX OF CLAY, IRON OXIDE ANO CALCIUM CARBONATE IRON OXIDE IS ABUNDANT AS REDDISH BROWN HEMATITE 9850-00 BROWN LIMESTONE WITH ORGANIC FRAGMENTS OF CALCITE ANO RADIOLARIA OF CALCITE. SOME OF WHICH HAVE BEEN PARTIALLY REPLACED BY OPALINE SILICA IN A MATRIX OF CLAY, IRON OXIDE AND CALCIUM CARBONATE ANO SOME OPAL IRON OXIDE IS ABUNDANT AS ALTERED HEMATITE 9900-50 SlLTSTONE: ESTIMATED SPHERICITY .69 ^ARTz: SUB-ANGULAR GRAINS EVENLY DISTRIBUTED. NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN TO BLACK IRREGULAR GRAINS WHICH SENO PROJECTIONS OUT INTO MATRIX CALCITE: ISOLATED FRAGMENTS MATRIX: OPAL, IRON OXIDE ANO CLAY COMBLETELY FILLING PORE SPACE 9950-80 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANQULAR GRAINS EVENLY DISTRIBUTED. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: BROWN TO BLACK IRREGULAR GRAINS WHICH SENO PROJECTIONS OUT INTO MATRIX CALCITE; ISOLATED FRAQMENTS MATRIX: OPAL, IRON OXIDE ANO CLAY COMPLETELY FILLING PORE SPACE WELL: TEXAS CRUDE 2-95 CLASSEN LOCATION: DAWSON COUNTY (SEC. 95, BLK. M, EL 4 RR 1980* FROM S 4 E OF SEC.) m¡mL THIN-SECTICN DESCRIPTIONS 8200-40 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED. GRAINS. LARGEST FOUR DIAMETERS SMALLEST GRAINS, GRAINS NOT IN CONTACT, SOME GRAINS CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: REDDISH BROWN HEMATITE WHICH FORMS PROJECTIONS INTO MATRIX ANO LAMINAE ANO AS ISOLATEO IRREGULAR DARK BROWN GRAINS CALCITE; ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; ISOLATED QRAINS CHLORITE 8300-10 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, LARGEST FOUR DIAMETERS SMALLEST GRAINS. GRAINS NOT IN CONTACT, SOME GRAINS CONTALN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS ANO BROWNISH MATRIX CALCITE; ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR; STRIATED TOURMALINE CRYSTALS AS INCLUSIONS IN A QUARTZ QRALN 8050-00 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR. UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS, SOME WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS AND BROWNISH MATRIX MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED GRAINS CHLORITE

8150-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORMLY SIZED. EVENLY DISTRIBUTED GRAINS. SOME WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS ANO BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED GRAINS CHLORITE

8310-50 ^ ^ «. SILTSTONE; ESTIMATED SPHERICITY .71 QUARTZ:* SUB-ANGULAR, UNIFORMLY SIZEO, EVENLY DISTRIBUTED GRAINS. SOME WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS ANO BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR ORGANIC MATERIAL: THREAD-LIKE CALCAREOUS ALGAL FRAGMENTS 59

^^SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANQULAR. UNIFORMLY SIZED, EVENLY DISTRIBUTED GRAINS, SOME WITH MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS AND BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR ORGANIC MATERIAL: THREAD-LIKE CALCAREOUS ALGAL FRAGMENTS 8^60-60 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED, UNIFORMLY SIZEO GRAINS, NOT IN CONTACT, CONTAINING MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS AND BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE; PLAGIOCLASE FELDSPAR; ISOLATED RAGGED GRAINS MANGANESE DIOXIDE

8460-00 DENSE BRO«W LIMESTONE

SILTSTONE: QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED, GRAINS NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS, GRAINS WITH THIN FILM OF OVERGROWTH OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS AND BROWNISH MATRIX CALC1 TE; IRREGULAR ISOLATED GRAINS MATIIR: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED GRAINS CHLORITE WELL: ClTIES PRODUCTION COMPANY |1, STARNES "D" LOCATION: TERRY COUNTY (SEC. 2. Buc. M, TTRR SURVEY 660» FROM S 4 1980» W OF SEC.)

tNTETVAL THIN-^vTION i^SCftlPTI^fiS 8040-50 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWN MATRIX CALCITE: EVENLY DISTRIBUTED ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

8050-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS AND BROWN MATRIX CALCITE: EVENLY DISTRIBUTED ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8100-50 ^ ^ ^ SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; IRREGULAR BLACK GRAINS ANO BROWN MATRIX CALCITE: EVENLY DISTRIBUTED ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE

8150—00 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ:* SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASGOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BLACK GRAINS ANO BROWN MATRIX CALCITE: EVENLY DISTRIBUTED ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR

**^^^*^ILTSTONE: ESTIWATEO SPHERICITY .67 QUARTZ:* SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; IRREGULAR BLACK GRAINS AND BROWN MATRIX CALCITE: EVENLY DISTRIBUTED ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR

^'^^^ILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDCI BROWN MATRIX AND IRREGULAR BLACK GRAINS CALCITE: IRREGULAR ISOLATED GRAINS 61 ¡JATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: WELL WORN ELONGATE ZIRCON CRYSTALS AND FRAGMENTS, ELONGATE CRYSTALS CONTALN ROD-SHAPED INCLUSIONS; PLAGIOCLASE FELDSPAR 8300-50 ^'fJ.ÜSíf' c.„ ESTIMATED SPHERICITY .69 ^^íflS. .ÍVr*'*®^*''' ^^'**-^ DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAlN MICROLITIC INCLUSIONS ?!íh'nw9!!í^"-í ^^ ^^^*" ASSOCIATED WITH IRON OXIDE. SHOWS SOME REPLACEMENT IRON OXIDE: BROWN MATRIX AND IRREGULAR BLACK GRAINS CALCITE: IRREGULAR ISOLATED GRAINS ¡íATRix: CUY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTMER MINERAL: PLAGIOCLASE FELDSPAR 8350-00 ^'!í?I2!f* c..«_ ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASGOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: BROWN MATRIX ANO IRREGULAR BLACK GRAINS CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR 8400-50 SILTSTONE; ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, CONTAINING MICROLITIC INCLUSIONS ANO WITH THIN FILMS OF OVERQROWTHS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTMER MINERALS: ISOLATED ZIRCON CRYSTALS FRAGMENTS, PLAGIOCLASE FELOSPAR. IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE

8450-00 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, CONTAINING MICROLITIC INCLUSIONS AND WITH THIN FILMS OF OVERGROWTHS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; AS BROWNISH MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MAMRIX; (XAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED ZIRCON CRYSTAL FRAQMENTS, PLAGIOCLASE FELDSPAR; IRREGULAR RAGGED GRAINS MANGANESE DIOXIOE

8710-50 SILTSTONE: ESTIMATED SPHERICITY .65 QUARTZ: ANGULAR, UNIFORMLY SIZED GRAINS (NOT AS CLOSE AS OBSERVED IN OTHER WELLS IN EITHER LOWER SPRABERRY OR DEAN) DECREASE IN ACTUAL AMOUNT OF QUARTZ GRAINS WITH CORRESPONDÍNG INCREASE IN MATRIX. SOME GRAINS CONTAIN MICROLITIC INCLUSIONS AND THIN FILMS OF OVERGROWTH. OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: SCATTERED, IRREGULAR BROWN GRAINS ANO BROWN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL ANO SMALL AMOUNT OF CALCIUM CARBONATE COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; CHLORITE (ISOLATED FRAGMENT) 8750—00 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR TO SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, SOME GRAINS WITH THIN FILMS OF OVERGROWTH ANO MICROLITIC INCLUSIONS; HIGHER PERCENTAGE OF QUARTZ GRAINS THAN IN 8710-90 THIN-SECTION INTERVAL 62 OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; SCATTERED, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR; ISOLATED GRAINS CHLORITE 8800-90 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; SCATTERED, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELOSPAR; PLAGIOCLASE FELDSPAR; ISOLATED FRAGMENT OF RUTILE WITH INCLUSIÓN 8890-00 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE; SCATTERED, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: AS IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELOSPAR; ISOLATED FRAGMENT RUTILE CRYSTAL; ISOLATED IRREGULAR GRAIN CHLORITE

8900-40 SlLTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE, SHOWS SOME REPLACEMENT IRON OXIDE: SCATTERED, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE; AS IRREGULAR I SOUTED GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: PLAGIOCLASE FELDSPAR ; ISOLATED GRAIN CHLORITE WELL: ClTIES SERVICE GREGORY §1 LOCATION: LYNN COUNTY (1980* FROM N 4 WL SEC. 12. BLK. 0-41. PSL SURVEY) mmÉL THIN-SECTION DESCRIPTIONS 7969-00 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; AS IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: IRREGULAR ISOLATED GRAINS IJATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL; MICROCLINE FELDSPAR 8000-50 SILTSTONE: ESTIMATED SPHERICITY .69 (^ARTz: SUB-ANGULAR. EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHIR MINERAL: PLAGIOCLASE FELOSPAR 8090-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASBOCIATED WITH IRON OXIDE IRON OXIDE: AS IRREGULAR DARK BROWN GRAINS ANO MATRIX CALCI TE: i RREGULAR ISOLATED GRAINS MATRIX: CLAY, IRON OXIDE ANO OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELDSPAR; PLAGIOCLASE FELOSPAR 8100-90 SILTSTONE: ESTIMATED SPHERICITY .67 QUARTZ: SUB-ANGULAR, EVENLY DISTRIBUTED GRAINS. NOT IN CONTACT. CONTAIN MICGOLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: AS IRREGULAR DARK BROWN GRAINS AND MATRIX CALCITE: IRREGULAR ISOLATED GRAINS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: MICROCLINE FELDSPAR; PLAGIOCLASE FELDSPAR

8200-90 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN PATCHES AND BROWN MATRIX CALCITE: ISOLATED RHOMBS AND IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERALS: ACICULAR CRYSTAL OF RUTILE, PLAGIOCLASE FELOSPAR 8300-50 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANQULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR RAGGED RHOMB OF SI DEBITE, IRREGULAR BROWN GRAINS ANO BROWN MATRIX CALCITE; ISOLATED RHOMBS SHOWING PARTIAL REPLACEMENT BY OPAL, AND ISOLATED IRREGULAR GRAINS 64 MATRIX; CLAY, IRON OXIDE AND OPAL AND SMALL AMOUNTS CALCIUM CARBONATE COMPLETELY FILLING PORE SPACE OTHER MINERALS: ISOLATED GRAINS CHLORITE AND PLAGIOCLASE FELDSPAR

8390-00 SILTSTONE; ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR GRAINS, UNIFORM IN SIZE, NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BROWN GRAINS AND BROWN MATRIX CALCITE: AGQREGATE MASSES CONTAINING RHOMBS ANO IRREGULAR GRAINS. OUTER EDGES OF MASSES SHOW PARTIAL REPLACEMENT BY SILICA MATRIX: CLAY, IRON OXIDE, OPAL AND SMALL AMOUNTS CALCIUM CARBONATE COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8400-90 SILTSTONE: ESTIMATED SPHERICITY .73 QUARTZ: SUB*ANGULAR GRAINS. UNIFORM IN SIZE, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; ISOLATED BROWN GRAINS AND BROWN MATRIX CALCITE: ISOLATED IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL ANO SMALL AMOUNTS CALCIUM CARBONATE COMPLETELY FILLING PORE SPACE OTHER MINRAL: PLAGIOCLASE FELDSPAR

8450-60 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORM, EVENLY SPACED GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS. SOME GRAINS SHOW STRAINING BY IRREGULAR INTER­ FERENCE COLORS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: ISOLATED BROWN GRAINS ANO BROWN MATRIX CALCITE: ISOLATEO IRREGULAR GRAINS MATRIX: CLAY, IRON OXIDE AND OPAL SNO SMALL AMOUNTS CALCIUM CARBONATE COMPLETELY FILLING PORE SPACE OTHER MINERAL: ISOLATED GRXINS CHLORITE

8700-50 SlLTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR, CLOUDY, UNIFORM GRAINS, SOME IN CONTACT, CONTAIN NUMERÓOS INCLUSIONS, SOME GRAINS SHOW STRAINING BY IRREGULAR INTERFERENCE COLORS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: IRREGULAR BROWN GRAINS ANO BROWN MATRIX (OLCITE: IRREGULAR ISOLATED GRAINS AND OCCASIONAL RHOMBS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: MICROCLINE FELDSPAR

8750-00 ^ , ^ SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. CLOUDY, UNIFORM GRAINS, SOME IN CONTACT, CONTAIN NUMERÓOS INCLUSIONS, SOME QRAINS SHOW STRAINING BY IRREGULAR INTERFERENCE COLORS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE; IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND OCCASIONAL RHOMBS MATRIX: CLAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: MICROCLINE FELDSPAR 65 8800-50 SILTSTONE: ESTIMATED SPHERICITY .71 QUARTZ: SUB-ANGULAR. UNIFORT^ GRAINS, NOT IN CONTACT. CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: PYRITIZATION OF FOSSIL. IRREGULAR BROWN GRAINS ANO BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND OCCASIONAL RHOMBS MATRIX; CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELOSPAR 8850-00 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORM SIZES, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: PYRITIZATION OF FOSSIL, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS ANO OCCASIONAL RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8900-90 SILTSTONE; ESTIMATED SPHERICITY .69 QUARTZ: SUB-ANGULAR, UNIFORM GRAINS, NOT IN CONTACT, CONTAIN MICROLITIC INCLUSIONS OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: PYRITIZATION OF FOSSIL. IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND OCCASIONAL RHOMBS MATRIX: CLAY, IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 8950-80 SILTSTONE: ESTIMATED SPHERICITY .69 QUARTZ: ANGULAR, FRAGMENTAL GRAINS. WIOELY SEPARATED BY MATRIX OPAL: CHIEFLY AS CEMENT ASSOCIATED WITH IRON OXIDE IRON OXIDE: PYRITIZATION OF FOSSIL, IRREGULAR BROWN GRAINS AND BROWN MATRIX CALCITE: IRREGULAR ISOLATED GRAINS AND OCCASIONAL RHOMBS MATRIX: (XAY. IRON OXIDE AND OPAL COMPLETELY FILLING PORE SPACE OTHER MINERAL: PLAGIOCLASE FELDSPAR 1 O z 1 o r8 •z 1 o oT > 2 o , _J O (0 UJ 1 lü Q y> o-l u. Sjo _ 1 5 1.^ < «o"*: ^ i-- Q ^0 5 * \o|

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