Galloway Creek Limestone and 

Ashlock and Drakes Formations 

(Upper Ordovician) in 

South-Central Kentucky

By GORDON W. WEIR, ROBERT C. GREENE, and GEORGE C. SIMMONS

" CONTRIBUTIONS TO STRATIGRAPHY

GEOLOGICAL SURVEY BULLETIN 1224-D

Prepared in cooperation with the 

Kentucky Geological Survey

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover)
CONTENTS

Page

Abstract__ _____________________________________________________ Dl

Introduction. _____________________________________________________ 1

Garrard Siltstone. ______________-___--_____-_________---------_--__ 6

Galloway Creek Limestone____________-______-____-_----__--_____ 6

Contacts- --___-___-_-____-_-_-______-____-_____----------_--_ 8

Extent, thickness, and probable correlatives..--__-_-------__--_-__ 8

Ashlock Formation----____.____.___-___.______.__.___-.______.____ 9

Tate Member..________________________________________________ 10

Gilbert Member_____-___________________________-_____________ 12

Stingy Creek Member________________________________________ 12

Terrill Member....._________________________________________ 13

Reba Member__-_----___---__--_-___-__________--__-____--_. 13

Upper contact__-___-_-__--_-___--_--___________--_-____-___. 16

Extent, thickness, and probable correlatives________--__--_--___. 16

Drakes Formation. ________________________________________________ 16

Rowland Member._________________________________________.__ 17

Preachersville Member._________________________________________ 18

Upper contact__-___-_--_-____--_-__---___-____----__-__----. 18

Extent, thickness, and probable correlatives_____________________ 18

References cited.__________________________________________________ 36

MEASURED SECTIONS

	Page 

SBCTION 1. Galloway Creek_____.__-._______.._____-__._____.__ D20

2a. Ashlock Cemetery West______________________-_-___._____ 23

2b. Ashlock Cemetery____________________________________ 24

2c. Lake Reba_____-.__-________--__________--___---__-_- 27

3a. East Fork of Drakes Creek___-._____._______-_.__.__ 30

3b. Rowland West.____________________.____-._ 32

3c. Preachersville Southeast.__-__________--__-_---__--___-_- 33

m
IV CONTENTS

ILLUSTRATIONS

Page 

FIGURE 1. Index map_______--___-___________-__________-____-_____ D2

2. Map of south-central Kentucky showing locations of stratigraphic sections._ _____________________________________ 2

3. Columnar section and nomenclature of Upper Ordovician

rocks overlying Garrard Siltstone________________________ 4

4. Map showing location of type section of the Galloway Creek

Limestone.___________________________________________ 7

5. Photograph of the Galloway Creek Limestone at the type

section._ _____________________________________________ 8

6. Map showing location of type and reference sections of the

Ashlock Formation. ___________________________________ 9

7. Photograph of the Tate, Gilbert, and Stingy Creek Members

of the Ashlock Formation at the type section.____________ 10

8. Photograph of the Back Bed of the Tate Member of the Ashlock

Formation_ _________________________________________ 11

9. Photograph of the Terrill and Reba Members of the Ashlock

Formation at the type section__.________________________ 14

10. Photograph of contact between the Ashlock and Drakes

Formations._ _--__--__--______-_-_______________-_____ 15

11. Map showing location of type section of the Drakes Formation. 17

12. Photograph of the Preachersville Member of the Drakes

Formation_ _________________________________________ 19
CONTRIBUTIONS TO STRATIGRAPHY

GALLOWAY CREEK LIMESTONE AND ASHLOCK AND

DRAKES FORMATIONS (UPPER ORDOVICIAN) IN

SOUTH-CENTRAL KENTUCKY

By GORDON W. WEIR, EGBERT C. GREENE, and GEORGE C. SIMMONS

ABSTRACT

Upper Ordovician rocks in south-central Kentucky are divided into lithologically distinct formations chiefly on the basis of contrasts in their mudstone and 

limestone content. From the top of the Garrard Siltstone to the top of the Ordovician are three newly defined map units; in ascending order, these are the Galloway Creek Limestone and the Ashlock and Drakes Formations.

The Galloway Creek Limestone is chiefly gray thin-bedded fossiliferous fineto medium-grained limestone having parting's 'and seams of greenish-gray shale; 

the lower part of the formation includes greenish-gray thin-bedded limy siltstone. 

The Galloway Greek ranges from about 80 to 130 feet in thickness.

The lower part of the Ashlock Formation is chiefly greenish-gray very sparsely 

fossiliferous limy and dolomitic mudstone; the middle pant consists of bluishand light-gray fossilifero<us aphaniitic to medium-grained and salty limestone; 

the upper part consists of greenish-gray unfossiliferous limy and dolomitic mudstone overlain by gray thin-bedded fossiiliferous miorograined, medium-grained, 

ajnd sility limestone. The Ashlock Formation ranges from about 125 to 145 feet in 

thickness.

The Drakes Formation is chiefly grayish-green unfossiliferous limy and dolomitic mudstone; 'the upper part contains than beds of yellowish-gray spiarsely 

fossiliferous fine-grained dolomitic limestone. The Drakes Formation ranges 

from about 120 to 150 feet in thickness.

INTRODUCTION

Geologic mapping and stratigraphic studies show the need for new 

names for lithologic divisions of the Upper Ordovician rocks in southcentral Kentucky (figs. 1 and 2). Previous stratigraphic nomenclature (fig. 3), developed by stratigraphers during the early part of this 

century, was largely concerned with paleontological divisions of Upper 

Ordovician strata near Cincinnati, Ohio, and in southeastern Indiana. 

The development of the nomenclature of the Upper Ord'ovician rocks 

of Ohio and Indiana is beyond the scope of this paper, but it has been 

recently reviewed by Gutstadt (1958, p. 518-521), Weiss and Norman

Dl
D2 CONTRIBUTIONS TO STRATIGRAPHY

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FIGURE 2. Locations of stratigraphic sections in south-central Kentucky: 1, 

Galloway Creek; 2a, Ashlock Cemetery West; 2b, Ashlock Cemetery; 2c, Lake 

Reba; 3a, East Fork of Drakes Creek; 3b, Rowland West; 3c, Preachersville 

Southeast.
(1960), and Fox (1962, p. 622-628). These authors pointed out that 

there has been much confusion between faunal units and rock units. 

Most of the named divisions in Ohio and Indiana were characterized 

by their fossils rather than lithology. The names of these divisions, 

called formations and members, were applied in south-central Kentucky to presumed time-equivalent units whose fossils or stratigraphic 

relations were similar to those of named divisions in Ohio 'and Indiana.

Whatever the suitability of the previous nomenclature in Ohio and 

Indiana, the stratigraphic names used there are inadequate for the 

Upper Ordovician rocks of south-central Kentucky because the lithology of this part of the section changes markedly between the two 

regions. The Upper Ordovician section in south-central Kentucky 

contains more mudstone, argillaceous limestone, and micrograined to 

fine-grained limestone than the approximately equivalent section near 

the Ohio Eiver.

The inadequacy of the nomenclature of the Cincinnati area for 

Upper Ordovician rocks of central Kentucky was long ago suspected 

by Foerste (1912, p. 22), who had earlier introduced many of the Ohio 

and Indiana names into Kentucky:

Owing to the considerable lithological and accompanying faunal differences 

between the Cincinnatian strata as exposed in Ohio and Indiana, and their 

approximate stratigraphical equivalents in central Kentucky, it may prove convenient, locally, to recognize only the greater subdivisions of the Cincinnatian 

strata, as proposed at the typical section, at Cincinnati, Ohio, and to adopt a 

somewhat different set of subdivisions southward.

The following names of stratigraphic units whose type localities are 

in Ohio and Indiana and which have been applied to units in central 

Kentucky (fig. 3) are inappropriate for the Upper Ordovician lithologic divisions in south-central Kentucky: Fairview, Fairmount, McMillan, Mount Auburn, Arnheim, Oregonia, Waynesville, Whitewater, 

and Liberty. To this list is added the name Sunset, applied to a unit 

whose type locality is in northeast-central Kentucky. These names 

have been used for stratigraphic units whose limits are defined by their 

fossils or whose typical lithology is not present in south-central Kentucky. The names Garrard, Tate, and Gilbert are retained for rockstratigraphic units whose type localities are in south-central Kentucky ; these units are more fully defined later in this report.

The strata in the south-central part of the State are divided into 

lithologically distinct formations and members chiefly on the basis of 

contrasts between mudstone and limestone. The proposed nomenclature (fig. 3) includes three formations that are defined in this paper; 

these are, in ascending order, the Galloway Creek Limestone, and 

Ashlock and Drakes Formations. The type sections of these formations are described in measured sections 1 (p. D20), 2b (p. D24), 

and 3a (p. D30).
D4 CONTRIBUTIONS TO STRATIGRAPHY

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D6 CONTRIBUTIONS TO STRATIGRAPHY

This report is based in large part on the geological mapping of 

Kentucky being conducted by the U.S. Geological Survey in cooperation with the Kentucky Geological Survey. Areas not currently being 

mapped were studied by the writers chiefly in late 1963 and early 1964. 

Of special help was the information contributed by E. R. Cressman, 

J. L. Gualtieri, W. L. Peterson, and F. A. Schilling, all of the U.S. 

Geological Survey.

GARRARD SILTSTONE

The Garrard Siltstone 1 (Campbell, 1898; Nosow and McFarlan, 

1960, p. 43) underlies the Galloway Creek Limestone. The Garrard, 

named for Garrard County, Ky., is chiefly limy siltstone and minor 

mudstone and limestone. The siltstone is gray and very limy where 

fresh, but in most outcrops it is weathered yellowish brown where much 

of the carbonate has been leached out. Most beds are 6 to 24 inches 

thick; thicker beds are commonly contorted. Many of the beds are 

obscurely laminated. The interbedded mudstone and limestone are 

mostly in lenses a few inches thick and a few feet to a few tens of feet 

long. Fossils are sparse except for brachiopods in sporadic lenses of 

limestone. The Garrard Siltstone is a moderately resistant unit that 

is about 10 to 100 feet thick in the area between Danville and Mount 

Sterling.

CALLOWAY CREEK LIMESTONE

The Galloway Creek Limestone is here named for Galloway Creek 

in north-central Madison County, Ky. The type section (measured 

section 1, p. D20) was described from roadcuts of Interstate Highway 

75, beginning about 0.4 mile south of the Kentucky River and extending southward to a point 0.6 mile north of Kentucky Highway 388 

(fig. 4).

The Galloway Creek Limestone is composed chiefly of limestone 

with interbedded shale and minor siltstone. The characteristic appearance of the formation in fresh cuts is shown in figure 5. Limestone, 

which makes up about 70 to 80 percent of the formation, is mostly gray, 

fine to medium grained, and in uneven beds 0.1 to 0.3 feet thick. 

Greenish-gray limy shale makes up about 15 to 25 percent of the formation and is interbedded with the limestone as partings or seams and, 

near the base, as thin sets as much as 0.5 feet thick. Limy siltstone

irThe Paint Lick Bed of Foerste (1906, p. 212), probably named for outcrops near the 

village of Paint Lick in Garrard County, was said to be the lower, more massive part of the 

Garrard (Foerste, 1909, p. 293,, and 1,912, p. 17, 49 ; McFarlan, 1943, p. 24 ; Nosow and 

McFarlan, 1960, p. 43), Mapping of the Garrard Siltstone in Garrard County and near 

Paint Lick shows no extensive divisions of the Garrard. The original definition of the 

Garrard by Campbell (1898), though generalized, is useful. The name Paint Lick is a 

later synonym of Garrard and is not used in this report.
Line of section 1 

(chevrons point 

stratigraphically 

upward)

FIGUBE 4. Location of type section of the Galloway 

Creek Limestone, Madison County, Ky.
D8 CONTRIBUTIONS TO STRATIGRAPHY

FIGURE 5. Characteristic interhedding of granular limestone with seams and 

partings of shale near middle of the Galloway Creek Limestone. Type section 

of the Galloway Creek Limestone (measured section 1), roadcut on southbound 

lanes of Interstate Highway 75 about 1.5 miles south of the Kentucky River 

in Madison County, Ky.

makes up about 5 percent of the Galloway Creek and is in even beds 

less than 0.5 feet thick which are intercalated with shale and limestone 

in the lower third of the formation. The siltstone is gray to greenish 

gray, weathers yellowish brown, and resembles siltstone in the Garrard 

Siltstone. The formation is very fossiliferous. Brachiopods and 

bryozoans are the most abundant and conspicuous megaf ossils.

CONTACTS

The Galloway Creek Limestone is transitional with the underlying 

Garrard Siltstone and the overlying Ashlock Formation. The lower 

contact is placed so that all relatively persistent beds of limestone are 

included in the Galloway Creek. The contact generally lies above all 

siltstone beds more than. 0.5 feet thick. The upper contact is placed so 

as to separate muddy limestone of the Galloway Creek from limy mudstone of the Ashlock. -.;.-,

EXTENT, THICKNESS, AND PROBABLE CORRELATIVES

The Galloway Creek Limestone has been mapped in Garrard and 

Madison Counties and has been recognized in sections from near Stan-
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D9

ford to near Mount Sterling. The formation is about 125 feet thick 

at its type locality and ranges from about 80 to 130 feet in thickness. 

Previous workers have correlated the beds here included in the Galloway Creek Limestone with the Fairmount Limestone Member of the 

Fairview Formation of the Cincinnati, area (McFarlan and Goodwill, 

1930).

ASHLOCK FORMATION

The Ashlock Formation is here named for the Ashlock Cemetery 

near U.S. Highway 27 about 0.1 mile north of the Dix Eiver in northeastern Lincoln County, Ky. The type section (measured section 2b, 

p. D24) was described from outcrops along the north bank of the 

Dix River and in readouts of U.S. Highway 27 north of the river 

(fig. 6).

The lower part of the Ashlock Formation is chiefly limy and dolomitic mudstone; the middle part is chiefly limestone and argillaceous 

limestone; and the upper part is greenish-gray unfossiliferous limy 

and dolomitic mudstone overlain by gray thin-bedded fossiliferous 

silty, granular limestone. Southwest of Richmond the formation is 

divisible into five members, which are in ascending order, the Tate, 

Gilbert, Stingy Creek, Terrill, and Reba Members.

Lines of section (chevrons 

point stratigraphically upward

FIGURE 6. Locations of type (2b) and reference (2a) sections of the Ashlock 

Formation, Lincoln County, Ky.
DIG CONTRIBUTIONS TO STRATIGRAPHY

TATE MEMBER

The Tate Member, here designated as the basal member of the Ashlock Formation, was originally described as the Tate "layer" (Foerste, 

1906, p. 212), later as the Tate Member of the McMillan Formation 

(Foerste, 1912, p. 48). It was probably named for outcrops along 

Tate Creek about 3 miles northwest of Eichmond, Ky. Foerste (1912, 

p. 48) stated that the Tate was typically exposed in Madison County, 

but he did not describe a type section. The description for the Tate 

Member at the Ashlock Cemetery section (measured section 2b, p. D25) 

is representative of the lithology of the member.

The Tate Member is chiefly greenish-gray laminated to thin-bedded 

sparsely glauconitic, limy to dolomitic mudstone commonly grading 

at the top to argillaceous limestone (fig. 7). Purplish-gray mediumgrained limestone, similar to limestone in the overlying Gilbert Member, occurs as a locally conspicuous unit, a few feet thick, about 10 

to 15 feet below the top of the Tate.

About 5 to 15 feet above the base of the Tate is a persistent set, about 

4 to 8 feet thick, of thin beds of olive-gray fine- to coarse-grained silty 

limestone containing silicified large brachiopods and bryozoans. This

f

9

FIGURE 7. Characteristic appearance in fresh cuts of the Tate Member (Oat), 

Gilbert Member (Oag), and Stingy Creek Member (Oas) of the Ashlock 

Formation. Type section of the Ashlock Formation, east side of U.S. Highway 27 about 0.5 mile north of the Dix River in Lincoln County, Ky. (See 

measured section 2b for description of units.)
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS Dll

unit, shown in figure 8, is a useful marker bed in south-central Kentucky and is here named the Back Bed of the Tate Member for representative outcrops along Back Creek in central Garrard County; 

the outcrop described in the Ashlock Cemetery section (measured section 2b, p. D26) is typical.

M.i.

FIGURE 8. Back Bed (below pick) of the Tate Member of the Ashlock Formation. Back Bed is light-gray fossiliferous limestone; rest of the Tate Member is chiefly greenish-gray limy mudstone. Roadcut on turnoff to Kentucky 

Highway 388 from northbound lanes of Interstate Highway 75, Madison 

County, Ky. , . . , , .,
D12 CONTRIBUTIONS TO STRATIGRAPHY

"V 

The Tate Member generally forms a moderate slope with light- 7

colored platy fragments of mudstone. At the base of the member and 

just above the Back Bed many of the fragments are of silicified mudstone. The Back Bed and locally a few limy units in the upper part 

of the member form minor ledges. The member contains few megafossils except for brachiopods and bryozoans in the Back Bed.

The Tate Member south of the Kentucky Kiver ranges from about 

30 to 80 feet in thickness. Its maximum known thickness is near Lancaster ; north and northeast of Richmond the upper part of the mem- ^ 

bei? grades to limestone and merges with an unnamed argillaceous and 

granular limestone member of the middle part of the Ashlock Formation. The Tate, including the Back Bed, has been identified in outcrops as far north as Mount Sterling.

GILBERT MEMBER

f

The Gilbert Member, here assigned to the Ashlock Formation, was 

named by Foerste (1912, p. 18, 23), probably for the village of Gilbert 

or for Gilberts Creek in northeastern Lincoln County, Ky. The mem- v 

ber was sketchily defined by Foerste, but as used near Gilberts Creek 

by McFarlan and others (1927) and by McFarlan (1929) the name applies to a thin resistant sequence of limestone with partings of limy \ 

siltstone. The outcrop shown in figure 7 at the Ashlock Cemetery section -('measured section 2b, p. D25) about 1 mile west of Gilbert is typical of the Gilbert Member. The limestone is bluish to olive gray, 

aphanitdc to medium grained, and in crinkly beds a few inches thick. 

Gray limy siltstone occurs as partings and seams less than 1 inch thick. 

The member contains abundant well-preserved megafossils, chiefly 

brachiopods and bryozoans. The member is about 15 feet thick near 

Gilbert and ranges from about 10 to 20 feet in thickness. North and 

northeast of Richmond the Gilbert loses its identity as it grades laterally into an unnamed unit of nonresistant argillaceous and granular 

limestone.

STINGY CHEEK MEMBER

The Stingy Creek Member of the Ashlock Formation is here named 

for representative outcrops of silty limestone and limy siltstone in roadcuts of Kentucky Highway 39 near Stingy Creek; the outcrop shown in 

figure 7 at the Ashlock Cemetery section (measured section 2b, p. D25) ris typical. The limestone is chiefly medium, light gray, fine to medium 

grained, and silty. It is obscurely thin bedded, partly in lenticles 

about an inch thick and a few inches long, and contains abundant 

brachiopods and bryozoans. The limy siltstone is chiefly light bluish 

gray and is gradational with the limestone with which it is interbedded. 

The Stingy Creek Member ranges from about 5 to 15 feet in thickness. *
CALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D13

Northeast of Richmond it cannot be separated from the underlying 

part of the Ashlock Formation.

The Stingy Creek Member is transitional for a few feet with the 

overlying Terrill Member. The contact separates rock that is dominantly limestone from that above which is mainly mudstone.

TEBBILL MEMBER

The Terrill Member is here named for outcrops near the settlement 

of Terrill, 4 miles south of Richmond. The type section of the member 

(measured section 2c, p. D28) is well exposed along Kentucky Highway 52 about 2 miles east of Richmond; the Ashlock Cemetery section 

(measured section 2b, p. D24) contains representative outcrops.

The Terrill is mainly composed of greenish-gray laminated limy or 

dolomitic mudstone as shown in figure 9. Weathered outcrops of the 

mudstone yield abundant small platy fragments. Many bedding surfaces are covered by ripple marks or mud cracks. The basal few feet 

of the member is a limy silty mudstone lacking distinct bedding. The 

member contains few megafossils. Bryozoans and brachiopods occur 

sparsely in the basal mudstone; and, locally, small chertified stromatolites occur near the top of the member. The Terrill Member ranges 

from about 5 to 15 feet in thickness and has been recognized in sections 

from near Stanford to near Winchester.

BEBA MEMBEB

The Reba Member is here named for its typical outcrops near Lake 

Reba on Kentucky Highway 52 about 2 miles east of Richmond (measured section 2c, p. D28); the Ashlock Cemetery section contains representative outcrops (measured section 2t>, p. D24.). The Reba Member 

is composed of micrograined limestone at the base, overlain by more 

or less silty, medium-grained limestone that at the top commonly 

grades into argillaceous limestone, as shown in figure 10. Limestone in 

the lower 2 to 6 feet of the member is commonly in ledge-forming beds 

as much as a foot thick, characteristically gray to grayish green, and 

aphanitic and micrograined to very fine grained; this limestone generally lacks megafossils but contains sparse ostracodes and abundant 

cylindrical markings a few millimeters across and a few centimeters 

long. Most of the limestone is fine to medium grained, has silty patches 

and partings, and is in uneven beds a few inches thick. Bedding is less 

distinct near the top where the limestone is more silty. . The fine- to 

medium-grained limestone and argillaceous limestone contain abundant 

fossils, chiefly bryozoans and brachiopods. The member ranges from 

about 10 to 25 feet in thickness and has been recognized in sections from 

near Stanford to near Winchester.

1777-052 O '65 3
D14 CONTRIBUTIONS TO STRATIGRAPHY

5sc^»§^ . :- -^- W*pV-' ^B- -.

FIGURE 9. Terrill and Reba Members of the Ashlook Formation. Below pick is 

greenish-gray laminated mudstone of the Terrill Member. Above pick is the 

Reba Member ; at the base about 3 feet of micrograined limestone grading above 

to medium-grained limestone and silty limestone. Type section of the Ashlock 

Formation, U.S. Highway 27, about 3 miles south of Lancaster, Ky. (See meas- 

,ured section 2b for additional description of units.)
CALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D15

FIGURE 10. Contact between the Reba Member of the Ashlock Formation and the 

Rowland Member of the Drakes Formation. Contact at pick head; silty limestone of the Reba Member below pick; transitional hackly weathering limy 

mudstone at pick assigned to the Rowland Member, platy-weathering limy mudstone about 1 foot above pick, characteristic of the Rowland Member. Lake 

Reba section about 2 miles east of Richmond, Madison County, Ky. (See 

measured section 2c for additional description of units.)
D16 CONTRIBUTIONS TO STRATIGRAPHY

UPPER CONTACT

The lithologies of the Ashlock Formation and overlying Drakes 

Formation are transitional for several feet. As shown in figure 10 

and described in measured sections 2b (p. D24), 2c (p. D28), and 3b 

(ip. D33), the upper part of the Reba Member of the Ashlock Formation is fossiliferous argillaceous limestone. In many places the top 

few inches of the Reba is made up of hackly weathering limy mudstone 

with partings and lenticles of fossiliferous limestone; above it is similar 

mudstone but without the limestone lenticles. The top of mudstone 

containing limestone lenticles or, where this mudstone is absent, the 

top of argillaceous limestone is the upper contact of the Ashlock Formation. Limy mudstone above the contact is hackly weathering for a 

thickness of a few inches to a few feet and is gradationally or sharply 

overlain by platy weathering mudstone characteristic of the Rowland 

Member of the Drakes Formation.

EXTENT, THICKNESS, AND PROBABLE CORRELATIVES

The Ashlock Formation has been mapped in parts of Lincoln, Garrard, Madison, Estill, and Clark Counties and has been recognized 

in sections from near Stanford to near Mount Sterling. It ranges 

from about 125 to 145 feet in thickness.

Previous workers have correlated the beds here included in the 

Ashlock Formation with the McMillan and Arnheim Formations 

of Ohio (Palmquist and Hall, 1961, pi. 1). The Tate and Gilbert 

Members together were correlated with the Bellevue and Corryville 

Members of the McMillan, and the unit here named the Stingy Creek 

Member of the Ashlock was correlated with the Mount Auburn Shale 

Member of the McMillan (Nosow and McFarlan, 1960, p. 45, 46). 

Most of what is here called the Terrill Member has been referred to 

the Sunset Member of Foerste (1910) of the Arnheim, and most of 

what is here called the Reba Member has,, been referred to the Oregonia Member of Foerste (1910) of the Arnheim (McFarlan and 

Goodwin, 1930; Nosow and McFarlan, 1960, p. 47).

DRAKES FORMATION

The Drakes Formation is here named for Drakes Creek in southern 

Garrard County. The type section (measured section 3a, p. D30) 

was described from outcrops along and near a dirt road connecting 

Preachersville and Cartersville, beginning near the East Fork of 

Drakes Creek (fig. 11).

The Drakes Formation is divisible into two members, the Rowland 

Member below and the Preachersville Member above.
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D17

-V.

Line of section 3a 

(chevrons point 

stratigraphically 

upward) J

FIGTJBE 11. Location of type s'ection (3a) of the Drakes Fonnation, Garrard

County, Ky.

ROWLAND MEMBER

The Rowland Member is here named for typical outcrops 1.3 

miles west of Rowland on U.S. Highway 27 on the outskirts of Stanford, Ky. (measured section 3b, -p. D32). -It is chiefly composed of 

grayish-green dolomitic or limy, sparsely glauconitic silty mudstone 

(fig. 10). The mudstone is obscurely bedded in fresh roadcuts but 

weathers readily to platy fragments a fraction of an inch thick and 

a few inches across. Many bedding surfaces are covered by ripple 

marks or mud cracks. Megafossils are absent or very sparse. The 

member is nonresistant, crops out poorly, and forms smooth slopes. 

The Rowland Member ranges from about 40 to 60 feet in thickness 

and has been recognized in sections from near Stanford to near 

Winchester.
D18 CONTRIBUTIONS TO STRATIGRAPHY 

PREACHERSVILLE MEMBER

The Preachersville Member is here named for typical outcrops exposed on Kentucky Highway 39 about 2 miles southeast of Preachersville, Ky. (measured section 3c, p. D33.) It is similar to the Rowland 

Member but contains 10 to 20 percent argillaceous, fine-grained dolomite or dolomitic limestone in resistant beds, a few inches to a few feet 

thick (fig. 12); commonly, the thicker beds are near the base of the 

member. Some of the dolomitic beds contain abundant poorly preserved bryozoans and sparse brachiopods. Because the dolomite beds 

are fairly resistant, the member has a much more ledgy outcrop than 

the underlying Rowland Member. In part of northern Madison 

County, and more sporadically in Lincoln County, the base of the 

member is marked by as much as 6 feet of fossiliferous limestone 

containing abundant colonial corals and stromatoporoids. The 

Preachersville Member ranges from 55 to 95 feet in thickness and has 

been recognized in sections from near Stanford to near Mount 

Sterling.

UPPER CONTACT

In most of south-central Kentucky the Drakes Formation is in 

sharp contact with the overlying Brassfield Dolomite of Early Silurian age. The basal few feet of the Brassfield is commonly silty 

dolomite with streaks and patches of yellowish-gray mudstone derived 

from the underlying Drakes. Exceptionally, as 1 mile north of Berea 

on U.S. Highway 25, the basal few feet of the Brassfield is breccia 

containing fragments, as much as 4 inches across, of dolomitic mudstone derived from the Drakes Formation. In parts of south-central 

Kentucky, as near Stanford, Silurian rocks are missing, and the 

Drakes is unconformably overlain by the Boyle Limestone or New 

Albany Shale of Devonian age.

EXTENT, THICKNESS, AND PROBABLE CORRELATIVES

The Drakes Formation has been mapped in parts of Lincoln, Garrard, Clark, Madison, and Estill Counties and has been recognized 

in exposures from near Stanford to near Winchester. The formation 

is uncommonly well displayed in cuts along the Louisville and Nashville Railroad south of Agawam about 6 miles southeast of Winchester. The Drakes ranges from about 120 to 150 feet in thickness. 

The beds here included in the Rowland Member of the Drakes Formation were correlated with the Waynesville Limestone of Ohio, and
CALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D19

the beds in the Preachersville Member of the Drakes were correlated 

with the Whitewater and Liberty Formations of Ohio and Indiana 

(Palmquist and Hall, 1961, pi. 1).

FIGURE 12. Characteristic outcrop of the Preachersville Member of the Drakes 

Formation, showing interbedded ledgy fine-grained limy dolomite and hackly 

weathering limy and dolomitic mudstone. Roadcut on east side of U.S. Highway 27, about 2 miles south of Stanford, Lincoln County, Ky.
D20 CONTRIBUTIONS TO STRATIGRAPHY

MEASURED SECTIONS *

SECTION 1. Galloway Creek

V.

[Type section of the Calloway Creek Limestone; reference section of the Garrard Siltstone. Section measured in roadcuts .along Interstate Highway 75 starting 0.4 mile 

south of the bridge over the Kentucky River and continuing southward for about 2 . miles to a point 0.6 mile north of the Kentucky Highway 388 (Boonesboro road) 

overpass over Interstate 75, Madison County, Ky. (Richmond North and Ford quad- ^- 

rangles). (See fig. 4.) Measured with Jacob staff, Abney level, and tape by G. C. 

Simmons and P. E. Cassity, June 1963] f

Ashlock Formation (incomplete) : V, 

Tate Member (incomplete) : Thickness 

12. Limestone, not measured. (feet) 

11. Shale, medium-gray (#4) 2, weathering grayish-green ^

(50 6/2)______________________________ 9.0 

Calloway Creek Limestone:

10. Limestone, medium-gray (#5), medium-grained; in uneven

beds mostly 0.2 to 0.3 ft thick but as much as 1.0 ft thick. ft 

Contains numerous inclusions, partings, and a few seams, 

as much as 0.1 ft thick, of greenish-gray (5GY 6/1 and 50 

6/1) shale. Upper 5 ft very argillaceous and grades into 

overlying shale of Tate Member of Ashlock Formation. ^ 

Abundant fossils including brachiopods and bryozoans__ 15. 8 

9. Limestone (75 percent) interbedded with shale (25 percent).

Limestone is medium gray (N5), medium grained, in uneven ^ 

beds as much as 0.5 ft thick; numerous greenish-gray argillaceous inclusions. Shale is medium light gray (#6) 

to greenish gray (5G 6/1), limy, in partings and beds as 

much as 0.2 ft thick. Abundant brachiopods and 

bryozoans ____________*._________ _ 13.1 

8. Limestone (70 percent) interbedded with shale (30 percent).

Two varieties of limestone are present. The more abundant *. 

limestone is medium light gray (#6) to medium dark gray 

(#4), finely mottled with white, very fine to medium ^ 

grained; abundant greenish-gray argillaceous inclusions; 

fossiliferous. The less abundant limestone is medium dark 

gray (JV4), very fine grained ; fossils sparse. Both varieties 

of limestone are in uneven beds which average 0.2 ft in '" 

thickness and reach a maximum thickness of 0.5 ft. Shale 

is medium gray (#5) to greenish gray (5G 6/1), limy, in 

beds as much as 0.2 ft thick. Abundant fossils, especially 

brachiopods and bryozoans____ 21.4 

7. Limestone (80 percent) interbedded with shale (20 percent). 

Limestone is medium gray (#5) to medium dark gray (#4), 

fine grained, in uneven beds 0.1 to 1.5 ft thick. Numerous ^ 

greenish-gray argillaceous inclusions and partings. Shale 

is greenish gray (50r 6/1), limy. Abundant brachiopods 

and bryozoans______ ___ 12.1

8 Color names with numbers based on color chart by Goddard and others (1948).
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D21

SECTION 1. Galloway Creek Continued

' Thickness 

Galloway Creek Limestone Continued (feet)

/ 6. Limestone (60 percent) interbedded with siltstone (20 percent) , and shale (20 percent). Limestone is light gray (NT) 

to medium dark gray (N4), light shades predominating, fine 

to medium grained, in uneven beds 0.3 to 0.4 ft thick. Nu-

^ merous greenish-gray argillaceous and silty inclusions and 

partings. Siltstone is greenish gray (5(2 6/1), limy, in beds

^ as much as 0.3 ft thick. Shale is greenish gray (5G 6/1),

) limy, in beds 0.1 to 0.2 ft thick. Abundant fossils, chiefly 

in limestone, include brachiopods, bryozoans, and sparse 

crinoid columnals; many fossils are fragrnental_______ 24. 3 

5. Limestone (60 percent) interbedded with shale (40 percent).

X Limestone is light gray (#7) to medium dark gray (#4), 

lighter shades predominating, very fine to medium grained, 

in uneven beds as much as 1.0 ft thick. Abundant greenishgray argillaceous inclusions. Shale is medium light gray 

(NQ) to grayish green (5G 6/1), limy, in part silty, in beds 

as much as 0.5 ft thick. Abundant brachiopods and 

bryozoans __________ _ 13.9

V 4. Limestone (50 percent) interbedded with siltstone (25 percent) and shale (25 percent). Limestone is medium light 

gray (NQ) to medium dark gray (N4) and greenish gray

j (5O 6/1), fine to medium grained, in uneven beds as much as 

0.5 ft thick. Siltstone is greenish gray (5GY 6/1) and 

weathers to dark yellowish brown (10YE 4/2) and dusky 

yellowish brown (IQYR 2/2). Siltstone layers increase in 

number and in thickness toward the base of the unit; beds 

from less than 0.1 ft thick near the top to 0.5 ft thick near

 * the base. Shale is medium light gray (NQ) to grayish green,

f limy, in beds as much as 0.4 ft thick. Abundant fossils, 

mostly brachiopods.

; NOTE. This interval is not completely exposed in the line 

of the measured section. Description is partly taken- from 

exposures on a tributary to Smith Fork of Calloway Creek 

about 1,000 ft to the east of Interstate Highway 75_____ 22.9

Total Calloway Creek Limestone____________________ 123. 5
D22 CONTRIBUTIONS TO STRATIGRAPHY

SECTION 1. Galloway Creek Continued 

Thickness 

Garrard Siltstone: (feet)

3. Siltstone (95 percent) interbedded with shale (5 percent). 

Siltstone is light greenish gray (5GY 7/1) ; weathers pale 

yellowish brown (WYR 4/2) to dusky yellowish brown 

(1QYR 2/2) in natural exposures. The fresher rock contains abundant interstitial calcium carbonate making up as X 

much as 25 percent of the rock. The more weathered darkto dusky-yellowish-brown rock is not calcareous, has lighter f 

specific gravity, and is punky. Beds are 0.3 to 3 ft thick ; in c 

general, the thicker beds occur toward the base of the unit; 

some beds are contorted. Shale is greenish gray (5GY 6/1) 

in partings and beds as much as 0.2 ft thick. Unit contains less than 5 percent limestone in thin lenses as much ^ 

as 10 ft long and 0.2 ft thick; limestone is very light gray 

(N8) to medium gray (JV5) and contains flakes and inclusions of siltstone and shale; moderately fossiliferous, 

chiefly brachiopods_________________________ 12.3 '

2. Siltstone, light-greenish-gray (5GY 7/1), weathering paleyellowish-brown (WYR 6/2). Where more intensely weathered is dark yellowish brown (10 YR 4/2) to dusky yellow- ^ 

ish brown (1QYR 2/2). Calcareous where not intensely 

weathered. Siltstone beds 0.3 to 8 ft thick with thicker \ 

beds toward base. Beds locally separated by thin shaly 

partings; a few beds in the lower 10 ft contain limestone «. 

stringers. Contorted beds common, characterized by flow 

rolls, rounded masses with complexly curved internal layering. Base gradational with limestone, shale, and siltstone 

of underlying unit; contact placed at top of highest persistent limestone bed of underlying formation; basal bed of *;, 

Garrard is as much as 8 ft thick___ _______ _ 21. 7

Total Garrard Silstone__________________________ 34. 0
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D23

SECTION 2a. Ashlock Cemetery West

[Reference section of the Ashlock Formation showing basal unit of the Ashlock Formation. 

Section measured along north bank of Dix River beginning 0.8 mile west of U.S. Highway 27, about 4 miles north of Stanford, Lincoln County, Ky. (Standford quadrangle). 

(See fig. 6.) Measured with Jacob staff and tape by G. W. Weir and J. C. Dills. 

October 1962.]

Ashlock Formation (incomplete) : Thickness 

Tate Member (incomplete) : (feet)

5. Mudstone, limy and silty, greenish-gray (5(rY 7/1), weathering gree.nish-gray (5GY 6/1) ; contains common to 

abundant flakes, 2 to 10 mm across, of bright-green clay 

mineral (glauconite?). Laminated to very thin bedded, 

0.05 to 0.5 in. thick ; smooth bedding surfaces ; sparse irregular ripple marks about 27 ft above base ; yields platy fragments 1 to 4 in. across ; no megafossils. Thickness given 

is top of good outcrop ; rest of Ashlock Formation is mostly 

covered. (See measured section 2b, p. D24.) _______ 34.0

4. Limestone, light-gray (NT) to yellowish-gray (5Y 8/1), very 

fine grained, silty to coarse-grained. Partly in very thick 

sets with obscure bedding and partly in thin sets 1 to 2 ft 

thick with obscure layering a few inches thick ; several limy 

shale partings, most conspicuous one is about 1 ft below 

top. Fossils common, chiefly large brachiopods, in part 

silicified. This unit is the Back Bed of the Tate Member, 

same as unit 2 of Ashlock Cemetery section ___ _ _ _ 4. 7

3. Mudstone, limy (95 percent) and silty limestone (5 percent). 

Limy mudstone is chiefly yellowish gray (5Y 7/2) , laminated 

to very thinly bedded (0.05 to 1.0 in. thick) ; yields platy fragments; forms steep slope; common fine- to medium-sized 

fossil fragments, large bryozoans common about 3 to 4 ft 

above base. Silty limestone is yellowish gray to pale yellowish brown (10Y.B 6/2), very fine grained; sparse 

brachiopods ; forms rough to smooth rounded ledge ; occurs 

as single bed 0.5 ft thick, 5.5 ft below top of unit __ _ - 11. 6

Measured Ashlock Formation (incomplete) _____ _ __ 50.3

Galloway Creek Limestone (incomplete) :

2. Limestone (90 percent) and limy shale (10 percent). Limestone is light gray (#7), chiefly fine to very fine grained and 

silty; becomes more silty upward, top 1 ft argillaceous and 

shaly weathering; in fairly even to slightly wavy beds 2 to 

4 in. thick. Interbedded with 1- to 3-in. thick irregular 

seams of limy and silty shale containing lenticles and partings of limestone. Contact with overlying limy mudstone 

fairly sharp_______________________ ____ 9.0

1. Limestone (90 percent) and limy shale (10 percent), lightgray (N7) to medium-gray (N5), chiefly very fine grained 

to fine-grained and argillaceous, in uneven beds, commonly 

1 to 4 in. thick. Fossils common, chiefly brachiopods. 

Partly covered; base of local exposure along road_ 8. 5

Measured Galloway Creek Limestone (incomplete)____ 17.5
D24 CONTRIBUTIONS TO STRATIGRAPHY

SECTION 2b. Ashlock Cemetery

[Type section of the Ashlock Formation and of the Gilbert and Stingy Creek Members of 

the Ashlock Formation and of the Back Bed of the Tate Member of the Ashlock 

Formation. Measured chiefly along U.S. Highway 27 beginning at Dix River beneath v 

bridge just west of mouth of Gilberts Creek and about 500 ft southwest of Ashlock 

Cemetery, Lincoln County, Ky., about 4 miles northeast of Stanford and 1 mile west of 

;Gilbert (Lancaster quadrangle). (See fig. 6.) Measured with Jacob staff and tape 

by G. W. Weir and R. C. Greene, November 1961] t

Drakes Formation (incomplete) : Thickness 

Rowland Member (incomplete) : (feet) 

15. Mudstone, limy and cherty, weathered to yellowish soil containing rectangular plates, 2 to 4 in. across, of white cherty 

shale weathering brownish gray and chips of grayishyellow (5Y 8/4) limy and silty shale; unfossiliferous. , 

Basal contact poorly exposed. Not measured; about 5 ft 

present; top of local exposure. Units 14b and 15 described 

from outcrops along abandoned road east of third roadcut 

north of Dix River. <

Ashlock Formation: 

Reba Member:

14b. Limestone (50 percent) and silty limestone (50 percent). 

Limestone is greenish gray (5GY 6/1) to light olive gray 

(5Y 6/1) ; weathered rock is about same colors; fossils 

common to abundant, chiefly brachiopods and bryozoans; 

mostly in thin beds % to 2 in. thick and interbedded with } 

silty limestone. Silty limestone is light greenish gray (50rY 

6/1) ; weathered rock is same color and grayish yellow 

orange (lOYjR 8/6) ; in beds less than 2 in. thick; poor 

fissility; brachiopods and bryozoans common to abundant. 

At top is a few inches of greenish-gray (5OY 6/1) limy x 

mudstone with partings of limestone; contains abundant 

small bryozoans. Whole unit forms steep rubbly, fossil- v 

strewn slope in third roadcut north of bridge. 12. 4 

14a. Limestone, light-olive-gray (5Y 6/1), aphanitic to micro- V 

grained; mostly in even beds 2 to 4 in. thick; abundant 

cylindrical markings about % in. in diameter and 1 to 2 in. 

long perpendicular to bedding, no megafossils. Resistant, , 

forms projecting ledge. Transitional with coarser grained 

limestone above; top rather arbitrary. Units 11 through ^ 

14a described from east side of third roadcut north of the 

Dix River________________________ _ 2.6 :

Total Reba Member______________________________ 15.0

Terrill Member:

13. Mudstone, limy and silty, moderate-olive (10Y 7/2) ; upper 

part more limy than near base, very thin bedded, fissile along 

bedding; unfossiliferous except for sparse silicified stromatolites at top; in natural outcrops forms low slope littered with 

platy fragments. Upper 1 ft more limy, somewhat gradational into Reba Member; upper contact placed at conspicuous parting plane below first thick limestone bed of unit 14a__ 10. 3
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D25 

SECTION 2b. Ashlock Cemetery Continued

A,shlock Formation Continued Thickness 

Terrill Member Continued (feet)

12. Mudstone, silty and sandy, greenish-gray (50rY 6/1) and 

light-greenish-gray (5GY 7/1) ; weathered rock is same colors; 

noticeable color contrast with underlying unit; much very fine 

sand admixed with silt; forms blocky ledge with irregular 

partings becoming more regular and very thin bedded upward ; 

.sparse large cylindrical bryozoans__________ - 1. 3

11. Mudstone, silty and limy, medium-greenish-gray (5C?Y 5/1) ; 

a single bed with a hackly surface due to irregular fractures; 

sparsely fossiliferous, contains a few brachiopods and bryozoans _________-________ ___^_____ 1.2

Total Terrill Member_______..________________ 12. 8

Stingy Creek Member:

10. Siltstone, limy (50 percent) and limestone (50 percent). Siltstone is dusky yellow (5Y 6/4), light bluish gray (55 7/1), 

and moderately yellowish brown (10Y 5/4) ; limy, grading to 

silty limestone; very poor fissility. Limestone is medium 

light gray (2V6) ; medium to coarse grained and silty; mostly in 

lumpy beds less than 3 in. thick. Limestone is about equal 

to siltstone in lower part of unit but less abundant and in more 

widely spaced beds in upper part. Whole unit very fossiliferous, contains chiefly brachiopods and bryozoans; less resistant 

than underlying unit; forms fossil-strewn slopes. Units 9 and 

10 described from second roaclcut north of the Dix River. __ 14. 2

Total Stingy Creek Member_________________________ 14. 2

Gilbert Member:

9. Limestone with partings of limy siltstone, bluish-gray (5B 

6/1), and light-olive-gray (5Y 6/1), weathering grayishorange-brown (10YR 7/2), mostly fine grained, in part 

aphanitic; siltstone mostly in partings, less than 1 in. thick, 

in crinkly bedding planes that are a few inches apart. Abundant fossils, chiefly brachiopods and bryozoans; also scattered 

gastropods, cephalopods, and crinoid fragments; fossils are 

locally silicified_____________________________ 15. 5

Total Gilbert Member___________________________ 15. 5

Tate Member (incomplete) :

8. Mudstone, silty, grading upward to argillaceous limestone. 

Silty mudstone is yellowish gray (5Y 7/2) ; contains much 

coarse silt; very limy with clusters of white calcite crystals. 

. Argillaceous limestone is yellowish gray (5Y 7/2) and light 

olive gray (5Y 6/1), medium and fine grained. Unit is in 

even beds 6 to 12 in. thick, forms smooth rounded ledges, and 

contains sparse brachiopods and bryozoans. Units 6, 7, and 

8 described from first roadcut north of Dix River______ 11. 0
D26 CONTRIBUTIONS TO STRATIGRAPHY 

SECTION 2b. Ashlock Cemetery Continued

Ashlock Formation Continued Thickness 

Tate Member (incomplete) Continued (feet) 

1. Limestone, purplish-gray (5P 6/1) to medium-light-gray 

(#6), medium- to coarse-grained; small clusters and vugs of 

white coarsely crystalline calcite; beds 2 to 4 in. thick with 

crinkly surfaces separated by partings, less than 1 in. thick, 

of silty limestone that weather to knobby ledges; common 

brachiopods and bryozoans. Unit is similar to Gilbert Member, unit 9 above. Forms conspicuous dark band in fresh cuts. 2. 5 

6. Mudstone, limy and silty (60 percent), and silty limestone 

(40 percent). Unit is greenish gray (5GY 6/1), weathers 

greenish gray (5G 6/1) and light olive gray (5F 6/1) ; 

micrograined, fine grained and silty, purest limestone at 

base and top of unit; common to abundant scattered flakes 

of bright-green clay mineral (glauconite?), flakes mostly 2 

to 5 mm across. Bedding planes commonly 6 in. to 2 ft 

apart. Conspicuous continuous parting plane 1.8 ft below 

top; forms near-vertical cliff in fresh roadcuts, but nearby 

weathered outcrops form rounded ledges less than 1 ft thick.

Very sparse fragments of brachiopods and bryozoans-- _- 15.1

5. Covered. (For description of rocks in this interval see measured section 2a, p. D23, Ashlock Cemetery West.) Units 1 

through 5 measured up cliff bordering Dix River_______ 21. 4

4. Limy mudstone (75 percent) and argillaceous limestone (25 

percent) ; both medium grained; mudstone laminae are 1 to 

25 mm thick, limestone beds about 1 in. thick in sets as much 

as 0.4 ft thick; forms steep, stepped slope littered with thin 

platy fragments__ _ _____ ___ _ 7.1

3. Mudstone, limy, greenish-gray (5GY 7/1) ; weathered rock is 

same color; in smooth laminae 1 to 20 mm thick. Scattered 

limy concretions, irregular discoidal lumps, a few inches in 

maximum diameter; fragments of brachiopods and bryozoans. Sparse large (0.5-in. diam) cylindrical bryozoans 

scattered through mudstone. Unit nonresistant, forms recess _____________________________ _ 3.2

2. Limestone, light-olive-gray (51' 6/1) and light-gray (#7), 

weathering yellowish-gray (5Y 7/2), very fine to mediumgrained and silty. Basal 1.3 ft consists of lenticles, 1 in. 

thick and 3 in. long, of medium-grained limestone in very 

thin bedded silty limestone matrix; very fossiliferous with 

large brachiopods. Middle 1.3 ft same as below but bedding 

less distinct. Shaly at top; fossils locally silicified; upper 

1.1 ft is thin bedded with wavy bedding planes, unfossiliferous. Unit is Back Bed of Tate Member._________ 3. 7
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D27

SECTION 2b. Ashloclc Cemetery Continued

Ashlock Formation Continued Thickness 

Tate Member (incomplete) Continued (feet) 

1. Mudstone, limy and dolomitic, greenish-gray (5G 6/1), 

weathering about grayish-yellow-green (5GY 7/2) ; in 

laminae and very thin beds as much as Vz in. thick; forms 

' stepped cliff. About 5 ft exposed to bed of Dix River; estimated total thickness based on exposures about 1 mile west of 

highway. (See measured section 2a, p. D23, for description 

of fully exposed unit and of contact with underlying Calloway Creek Limestone.)______________________ 11.6

Total Tate Member____________________________ 75. 6

Total Ashlock Formation _________________________ 133. 1

SECTION 2c. Lake Reba

-\

[Type Section of the Terrill and Reba Members of the Ashlock Formation. Measured in 

roadcuts along Kentucky Highway 52; beginning about 2 miles east of Richmond, 

Madison County, Ky. (Moberly quadrangle).. Measured with Jacob staff and tape by

y R. C. Greene and G. C. Simmons, December 1962 ; additional description by G. W. Weir. 

January 1964]

Drakes Formation (incomplete) : Thickness 

J Preachersville Member (incomplete) : (feet) 

9. Miid'Stone (65 percent) and dolomitic limestone (35 percent). 

Mudstone is greenish gray (5GY 6/1) ; in even beds or sets 

of beds 1 to 6 in. thiick, probably laminated in part ; bedding 

generally obscure. Limestone is dolomitic and argillace-

.. ous, greenish gray (5GY 6/1), very fine to fine-grained ; argillaceous patches and streaks ; in even beds, 0.2 'to 12 in.

' thick, thicker near top ; makes up about 10 percent of unit 

near base, increasing to about 70 percent near top. Very

^ sparse poorly preserved bryozoans. Thickness approximate ; difference in altitude is 26.4 ft ; dip is about % ° B. 

(approx) along line of section _____ _ __________ 30 

8. Limestone, dolomitic and in part argillaceous, very pale yel-

-*" lowisih brown (10Y.R 7/2) and medium-dark- to medkimlight-gray (#4-6) and greenish-gray (5GY 6/1) ; 

weathered rock is same colors, faintly mottled grayish green

- and grayish orange ; very fine grained ; argillaceous to 

medium grained ; coarser near top; in even beds 3 to 12 in. 

thick ; florins resistant ledge. Sparse poorly preserved 

bryozoans _______________________________ 4. 6

Measured Preachersville Member (incomplete; approximate) _ _ _ _ 35
D28 , CONTRIBUTIONS TO STRATIGRAPHY

SECTION 2c. Lake Reba Continued

Drakes Formation (incomplete) Continued Thickness 

Rowland Member: (feet) 

1. Covered________________________________ 5

6c. Mudstone, limy, light-olive- to greenish-gray (5Y, 5&F, 5# 

6/1) ; sparse patches of green clay mineral (glauconite?) ; 

evenly laminated to very thin bedded in sets a fraction of an 

inch to as much as 18 in. thick; mostly splits along sets *4 to 

% in. thick. No fossils seen. As a whole, nonresistant but 

more resistant than underlying unit; forms minor overhang 

at base. Thickness approximate; difference in altitude is 

28.2 ft; dip is about %° E. (approx) on line of section___ 35

6b. Mud/stone, greenish-gray (5GY 6/1) ; bedding obscure; mostly 

nonfissile except for rough partings near top; face is coarse- . 

ly 'hackly with many small angular and curving surfaces; 

along with underlying unit forms recess. Grades through a 

few inches into overlying unit, which unit resembles except 

for .lack of bedding; basal contact sharp. No fossils seen_ 2. 3

6a. Shale, limy, dark-greenish-gray (5GY 5/1) ; 'sparse glauconite ( ?) ; ^roughly laminated; weathered outcrop yields abundant fine chips; nonresistant; very sparse brachiopad( ?) 

fragments at base; gradational through about 1 in. at base . 9

Total Rowland Member (approximate)__________________ 43

Measured Drakes Formation (incomplete; approximate)______ 78 

Ashlock Formation (incomplete) : 

Reba Member:

5. Limestone, argillaceous, light-olive- to greenish-gray (5Y-, 

5GY 5/1) ; minutely mottled with green clay mineral (glauconite?) ; fine grained. In even sets mostly 1 to 2 ft thick 

with obscure beds 2 to 3 in. thick. Moderately resistant; 

base locally forms minor overhang. Fossils common, mostly 

brachiopods and bryozoans___________________ 7. 2

4c. Mudstone (70 percent) and limestone (30 percent). Mudstone is limy, medium dark gray (#4), roughly laminated, 

in sets 1 to 12 in. thick; no fossils seen. Limestone is medium gray (N5) to dark olive gray (5Y 3/1), fine grained, 

argillaceous, in lensing beds a few inches thick, mostly in 

basal 1 ft of unit. Unit nonresistant; forms recess___ 2. 7

4b. Limestone (90 percent) and mudstone (10 percent). Limestone is medium gray (#5) and dark olive gray (5Y 3/1), 

aphanitic to coarse grained but mostly medium and coarse 

grained, fossil fragmental, sparse greenish-gray glauconite (?), and sparse pyrite. In even beds 2 to 12 in. thick, 

decreasing in thickness upward. Fossils common to abundant, low-spired gastropods especially abundant, brachiopod 

fragments common. Mudstone is dark gray (#3), limy; 

roughly laminated as partings and thin interbeds as much as 

2 in. thick ; unfossiliferous- _ _ _ - 3. 0
CALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D29

"j^ SECTION 2c. Lake Reba Continued

' Ashlock Formation Continued Thickness 

Reba Member Continued (feet) 

4a. Limestone, niedium-light-gray (NQ) ; mottled and streaked 

with light-gray (JV7) ; aphanitic to fine-grained, mostly 

micrograined; sparse pyrite. Basa.l bed is 1.1 ft thick,

A overlain by sets of laminae and thin beds as much as 3 in. 

thick. Markedly resistant, base is prominent ledge. Mostly 

unfossiliferous except for sparse fragments of bryozoans and 

and brachiopods; ostracodes common in top layer; basal 

bed and some other layers characterized by fucoidal markings, nearly vertical cylinders of medium-light-gray finegrained material in aphanitic matrix. _ 2. 6

Total Reba Member____________________ 15.5

Terrill Member:

3. Mudstone, limy, greenish-gray (5GY 6/1 and 5C? 6/1) ; mostly 

laminated and splitting smoothly along sets a fraction of an 

inch thick, but a few sets as much as 6 in. thick resemble 

unlaminated unit below; weathered outcrop yields abundant.plates. Near top, 0.5 to 2.0 ft below contact, beds 

are very limy, grading toward micrograined limestone of 

overlying unit; top 0.5 ft is grayish-brown shale. Fossils 

absent except for sparse small fragments in limy beds near 

top _________________________________ 8. 5

2. Mudstone, limy, light-olive- to greenish-gray (5Y-, 5GY 6/1), 

streaked and mottled with brownish-gray (5YR 4/1), 

weathering light-olive-gray to pale-olive (5Y-, 10Y 6/2) ; 

sparse fine-grained, greenish glauconite(?). A -single set 

with faint irregular thin bedding, which is less distinct than 

bedding in overlying or underlying units. Weathers to an 

irregular face with smooth curving surfaces; nonresistant, 

forms recess. Base marked by 1 to 2 in. of dark-gray claystone, mostly plastic, water saturated. Fossils sparse, a few 

small cylindrical bryozoans___________________ 2. 5

Total Terrill Member___________________________ 11. 0

Stingy Creek Member (incomplete) :

1. Limestone, argillaceous, medium-gray (N5), less commonly 

olive-gray (5Y 5/1), fine-grained, silty and clayey; roughly 

laminated in obscure sets 2 to 4 in. thick. Fossils common, 

mostly brachiopods and bryozoans. Base of local exposure.. 9. 5

S' -__,._ 

Measured Ashlock Formation (incomplete)__.__________ 36.0
D30 CONTRIBUTIONS TO STRATIGRAPHY

SECTION 3a. East Fork of Drakes Creek

[Type section of the Drakes Formation. Measured about 5 miles due west of Cartersville and about 1 mile west of Button Lick Knob, Garrard County, Ky. Paint Lick 

quadrangle). Section begins about 500 ft southeast of East Fork of Drakes Creek 

and thence along dirt road connecting with road along Harmons Lick ; at top of first 

hill (alt 1,014 ft) section measured along westward-trending ridge. (See fig. 11.) 

Measured with Jacob staff and rule by G. W. Weir and J. C. Dills, October 1962]

Thickness 

Brassfield Dolomite (incomplete; Silurian) : (feet)

11. Dolomite and limy dolomite, grayish-orange (5Y 8/4), streaked 

very dusky red (10.R 2/2) and moderate-reddish-brown 

(10R 4/6) ; commonly coated with pale-yellowish-brown 

(WYR 6/2) ; fine to medium grained. Mostly weathered to 

dark-yellowish-orange (WYR 6/6) residuum which forms a 

sharp, conspicuous contact with the grayish-yellow soil of 

unit 19. Not measured ; only about 5 ft present on hilltop ; 

about 0.3 mile west of this point, Brassfield Dolomite is well 

exposed and is about 20 ft thick. 

Drakes Formation (Ordovician) : 

Preachersville Member:

10. Shale, silty, pale-greenish-yellow (10Y 8/2) ; in very thin beds 

0.2 in. thick. Poorly exposed ; mostly weathered to grayishyellow (5Y 8/4) soil; nonresistant, forms gentle slope___ 17. 0

9. Dolomite, limy and silty, grayish-orange (10F-B 7/4), weathering grayish-yellow (5Y 8/4) ; in thin beds 1 in. thick; weathers to small irregular chunks; more resistant than overlying 

unit. In part very poorly exposed; probably contains some 

shaly siltstone____________________________ 8. 0

8. Dolomite, silty; probably similar to underlying unit but poorly 

exposed; probably contains much limy or dolomitic mudstone. At top is a bed of bryozoan silty dolomite that is 

yellowish gray (5Y 7/2) and spotted dark yellowish orange 

(10Y.R 6/6) ; finely crystalline, silty and very fine sandy; 

about 50 percent of the rock is made up of branching bryozoans, 1 to 4 mm in diameter; bed is 0.5 ft thick. (Section 

offset along top of this bryozoan dolomite bed across small 

saddle east of barn to outcrops on point below stock pond.) __ 11. 5

7. Dolomite, silty, grayish-yellow (5F 8/4) to light-gray (NT), 

fine-grained, very fine sandy, in thin beds a few inches thick; 

forms minor bench; abundant very small bryozoans at top_ 1. 3

6. Covered ; grayish-yellow soil_____________________ 6. 3

5. Mudstone, dolomitic and silty (50 percent), and limy mudstone 

(50 percent) ; very poorly exposed. Dolomitic silty mudstone is light gray (N7), in thin beds 1 to 2 in. thick and interbedded with limy mudstone. Limy mudstone is pale olive 

(10Y 6/2), clayey, poorly laminated ; somewhat plastic when 

wet ___________________________________ 21.2
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D31

1 SECTION 3a. East Fork .of Drakes Creek Continued

1 Drakes Formation (Ordovician) Continued Thickness 

Preachersville Member Continued (feet) 

4. Mudstone and dolomitic to argillaceous dolomite, light-gray 

(NT) to medium-gray (M>), weathering yellowish-gray 

(5Y 7/2 and 5Y 8/1), silty, in part limy; bedding obscure

^ but lacks even bedding of underlying unit. Weathered surface has irregular nodular appearance suggestive of fossil 

markings ; contains small nodules and streaks of light-orange 

calcite and dolomite, a few with sphalerite, perhaps recrystal-

\ lized fossil material; no fossils seen. Fairly resistant, forms

rough ledge_____________________________ 9. 0

Total Preachersville Member______________________ 74. 3

Rowland Member:

3. Mudstone, limy, light-greenish-gray (50? 7/1) and grayishyellow-green (5GY 7/2), weathering pale-olive (lOY 6/2) ; 

mostly limy, a few beds dolomitic, probably clayey in part as 

in 6-in.-thick bed about 20 ft above base. Unit appears 

unstratified internally in fresh cuts but weathers to thin 

beds less than 1 in. thick; ripple marks noted about 40 ft 

above base, mud cracks on slabs in float. Weathered outcrop yields platy fragments a fraction of an inch to several 

inches in diameter. Exposed in roadcut, little natural 

outcrop. No fossils seen_ _ _______ _ 52. 4

2. Mudstone, clayey; mostly covered on line of section. At base 

is seam of plastic claystone that is pale yellowish green 

(lOCrY 7/2) and a few inches thick; rest of unit is covered 

by platy debris from overlying unit. About 1,100 ft north of 

main line of section, most of this interval is well exposed 

and consists chiefly of mudstone that is light greenish gray 

(5GY 7/1) to greenish gray (5GY 6/1), very silty, and 

dolomitic to slightly limy; sparse dark-green spots of glauconite(?); appears structureless where fresh but is obscurely laminated and, where weathered, parts readily 

along smooth planes % to ^ in. apart; yields platy fragments about a/4 in. thick and several inches in diameter; unfossiliferous. Basal 2.5 ft is clayey mudstone, generally 

similar to mudstone described but finer grained, more poorly 

bedded, and less fissile; sparse fragments of brachiopods in 

basal foot_____________________________ 8.3

Total Rowland Member___________________________ 60. 7

NJ- Total Drakes Formation___________________________ 135. 0

Ashlock Formation (incomplete) : 

N Reba Member (incomplete) :

1. Limestone, medium-light-gray (#6) and yellowish-gray (5Y 

8/1) ; fine to medium grained, very argillaceous in top 5 ft; 

in rough-surfaced beds a few inches thick ; abundant brachiopods and bryozoans. Not measured; about 15 ft exposed 

X locally.
D32 CONTRIBUTIONS TO STRATIGRAPHY

SECTION 3b. Rowland West

[Type section of the Rowland Member of the Drakes Formation. Measured in readouts 

along U.S. Highway 27 on outskirts of Stanford, about 1.2 miles west of Rowland, 

Lincoln County, Ky. (Stanford quadrangle). Measured with Jacob staff and rule 

by G. W. Weir, July 1964]

Drakes Formation (incomplete) : Thickness 

Preachersville Member (incomplete) : ,(feet)

8. Limestone, dolomitic, grayish-orange (1QYR 7/4), mottled 

light-olive-gray (5Y 5/1) ; weathered rock is about same color; commonly coated dark-olive-gray (5Y £-4/1) ; very fine 

to fine grained; sparse scattered clusters, a fraction of an 

inch across, of orange and white coarsely crystalline calcite. 

In rough beds a few inches to about 1 ft thick with seams 

of mudstone as much as 2 in. thick; forms prominent ledge 

about 1 ft thick at base; minor, less prominent ledges 

above. Only basal foot well exposed near hilltop; thickness approximate_______ ___ 5. 0 

Rowland Member:

7. Mudstone, dolomitic, light-greenish-gray (5&Y 8/1) and yellowish-gray (5Y 7/2), weathering about grayish-orange 

(10Y-R 7/3) and pale-greenish-yellow (10Y 8/2) ; mostly 

silt probably with interstitial clay, and flakes of claystone a 

fraction of an inch across; in thin even beds a fraction of 

an inch to an inch thick; no megafossils. Uess dolomitic, 

less resistant than underlying or overlying unit. Poorly 

exposed on gently slope______________________ 4.0

6. Mudstone, dolomitic, chiefly yellowish-gray (5Y 7/2), in 

part mottled dark-yellowish-gray (5Y 6/2), argillaceous, 

very fine grained; some beds probably argillaceous dolomite ; in even beds % to 2 in. thick; cleaves along smooth 

partings % to 1 in. apart; no megafossils; mottling perhaps 

of organic origin. More resistant than underlying and 

overlying units; forms ledge at top of roadcut, forms slope 

in natural outcrop 3.0

5. Mudstone, limy and dolomitic, greenish-gray (5Y 6/1), 

weathering yellowish-gray (5Y 7/2), argillaceous, very fine 

grained; some beds probably argillaceous limestone and 

dolomite with flakes and partings of mudstone; laminated 

and in even beds a fraction of an inch to several inches 

thick; splits along smooth partings a fraction of an inch ^ 

to an inch apart; no megafossils______________ 29.0

4. Mudstone, limy, greenish-gray (5GY 6/1), weathering light- '- 

olive-gray (5Y 6/1) and yellowish-gray (5Y 7/2), argillaceous, very fine grained; some beds probably argillaceous 

limestone; dark-green glauconite(?) common near base; 

discontinuous siliceous white band, 0 to 2 in. thick, about 8.5 "^ 

ft above base; laminated and in thin even beds commonly 

% to 1 in. thick, a few beds s'everal inches thick; bedding 

obscure in fresh cuts but brought out by weathering; 

cleaves readily along smooth partings % to 1 in. apart; 

weathered outcrop yields plates and blocks; no megafossils 

noted. Top placed at top of hackly weathering interval 

1 to 3 ft thick, forming minor niche. More resistant than * 

underlying unit but along with units 8, 9, and 10 forms 

moderate slope__________________________, 22.1 '
SECTION 3b. Rowland, West Continued

Drakes Formation (incomplete) Continued Thickness 

Rowland Member Continued (feet) 

3. Mudstone, greenish-gray (5GY 6/1), slightly limy; darkgreen glauconite( ?) common; crudely laminated; weathers 

to small chips ; no megafossils ; nonresistant, forms niche 

below more resistant mudstone of unit 7 _______ __ 0.9

Total Rowland Member __________ ____ ___ 59

Measured Drakes Formation (incomplete)___________ _ 64

Ashlock Formation (incomplete) : 

Reba Member (incomplete) :

2. Mudstone (75 percent) and limestone (25 percent). Mudstone is greenish gray (5GT 6/1), limy, crudely laminated; 

weathers to small chips. Limestone is argillaceous, greenish gray (50-Y 6/1), very fine grained, intermixed with 

mudstone; fossils fragmental; common grayish-green clay 

mineral (glauconite?) ; in lenticles % to ^4 in. thick and a 

few inches long scattered through mudstone; very f ossiliferous, contains abundant fine to very coarse fragments of 

bryozoans and brachiopods. Nonresistant unit, forms fossilstrewn slope. Presence of limes'tone differentiates this unit 

from overlying unit; contact placed at top of limestone 

lenticles interstratified with mudstone____________ 1.0

1. Limestone, argillaceous, greenish-gray (5G1 6/1) ; weathered 

rock is about same color; poorly sorted, very fine to coarse 

grained, but mostly fine to medium grained; intermixed 

with 10 to 40 percent mudstone; obscurely bedded, probably in crenulated beds 1 to 3 in. thick. Very fossiliferous, 

chiefly bryozoans and brachiopods. Nonresistant, 

weathers to fossil-strewn rnbbly slope. Not measured; 

about 10 ft exposed in highway cut and ditch.

SECTION 3c. Preaohersville Southeast

[Type section of the Preachersville Member of the Drakes Formation. Measured southward in gully and roadcuts along Kentucky Highway 39 beginning about 2 miles southieast of Preachersville, Lincoln County, Ky. (Lancaster quadrangle.) Measured with 

Jacob staff and rule by G. W. Weir, July 1964. Thicknesses adjusted for local dip of 2° 

iSE.]

Brassfield Dolomite (incomplete; Silurian) :

10. Limestone, dolomitic, pale-grayisih-orange (10Y.B 8/4), with 

streaks of dark-yellowish-orange (WYR 6/6) ; very fine to 

fine grained; in rough beds several inches thick; no fossils 

noted. Mostly weathered to moderate-yellowish-brown 

(10Y-R 5/4) soil with scattered blocks a few inches to a few 

feet across. Not measured ; residuum is about 3 ft thick on 

hilltop at end of section about 800 ft southeast of starting 

point.
D34 CONTRIBUTIONS TO STRATIGRAPHY

SECTION 3c. Preachersville Southeast Continued

Drakes Formation (incomplete ; Ordovician) : Thickness 

Preachersville Member: (feet)

9. Shale, silty and probably do.lomitic, moderate- to pale-greenishyellow (10F 7-8/2) ; in smooth even laminae and thin beds 

as much as 1 in. thick; very fissile along bedding planes; 

nonresistant, forms gentle slope. No fossils noted-_ '20

8. Mudstone (80 percent) and limy argillaceous dolomite (20 percent). Mudstone is light greenish gray (5OY 7/1), slightly 

limy, mostly obscurely bedded, in part laminated; hackly 

weathering yielding small chunks commonly % to % in. 

across; no megafossils noted ; curly markings % in. across 

and several inches long resembling worm tracks in lower 

part of unit; makes up Tower % of unit and interbedded 

with dolomite in top %. Dolomite is limy, argillaceous, 

pale grayish orange (10YR 8/2) and light greenish gray 

(5GY 7/1), very fine grained, in even beds about 1 in. thick ; 

no fossils noted. Unit forms slope with ledgy top___ 4. 5

1. Dolomite (70 percent) and mudstone (30 percent). Dolomite 

is argillaceous and limy, yellowish gray (5Y 7/2) to grayish 

Orange (1QY.R 7/3), chiefly very fine and fine grained, with 

streaks of greenish-gray mudstone; in somewhat rough beds 

*4 to 1% in. thick; sparse poorly preserved cylindrical 

bryozoans in a few thin beds. Mudstone is dolomitic, 

light greenish gray (5GY 7/1) to yellowish gray (5Y 8/1) ; 

common to abundant intermixed fine-grained dolomite; 

in obscure and irregular, lumpy discontinuous beds commonly ^4 to 1% in. thick; closely interstratified with dolomite; no fossils noted. Whole unit relatively resistant, 

sets of beds of dolomite form ledges_________ 15. 5

6. Mudstone, dolomitic; similar to dolomitic mudstone in overlying unit 7; nonresistant, forms slope ; very sparse poor.ly preserved small cylindrical bryozoans____________ 6

5. Dolomite (50 percent) and mudstone (50 percent). Dolomite 

is argillaceous, yellowish gray (5F 7/2-8/1) and medium 

gray (JV5), and pale orange (1QYR 7/2), very fine to fine 

grained, silty ; intermixed streaks and patches of mudstone; 

slightly limy, with clusters, % to % in. across, of paleyellowish-orange calcite crystals; mostly in fairly even 

beds 1 to 3 in. thick; base marked by uneven bed 4 to 8 in. 

thick; muddier parts contain common "worm" markings, 

about % in. across, emphasized by slight color contrasts; 

very sparse poorly preserved bryozoans. Mudstone is dolomitic, greenish gray (5GY 6-7/1) ; contains intermixed grayish-orange (WYR 7/3) stringers and patches of very fine 

grained dolomite; obscurely bedded; hackly weathering; 

common "worm" markings and very sparse very poorly 

preserved small cylindrical bryozoans and small fragments 

of brachiopods(?). Whole unit relatively resistant; beds 

of dolomite form minor ledges_____________ 16 

4. Mudstone, dolomitic, grayish-green (5Gr 6-7/1) ; similar to 

mudstone in unit 5; less resistant than underlying or overlying unit ___________ 11
GALLOWAY CREEK LIMESTONE, ASHLOCK AND DRAKES FORMATIONS D35

SECTION 3c. Preachersville' Southeast Continued

Drakes Formation (incomplete; Ordovician) Continued Thickness 

Preachersville Member Continued ' (feet) 

3. Mudstone, limy (50 percent), grading to fossiliferous argillaceous limestone (35 percent) and, at top, grading to dolomitic mudstone (15 percent) ; yellowish gray (5F 8/2), 

greenish gray (5GY 6/1 and 5G 6/1) ; weathered rocks are 

same colors and light olive gray (5F 6/1) and light greenish 

. gray (50? 7/1). At base is about 1 ft of poorly bedded unfossiliferous limy mudstone, overlain by about 2 ft of very 

limy mudstone containing common to abundant lenticles, a 

few inches long and less than an inch thick, of fossiliferous 

argillaceous limestone, grading to fossiliferous argillaceous 

limestone with a few seams of mudstone and in top 1 ft 

grading to unfossiliferous resistant dolomitic mudstone; 

separated from dolomitic mudstone of unit 4 by conspicuous 

parting, commonly iron stained. Bedding generally obscure 

throughout unit. Limy rocks sparsely to abundantly fossiliferous ; most conspicuous are colonial corals, as much as 2 

ft across in layer about 2 ft below top of unit; smaller colonial corals and stromatoporoids common about 2.5 ft below 

top; brachiopods and bryozoans, sparse to very abundant 

beginning about 2 ft above base and continuing to about 1.5 

ft below top. Unit generally nonresistant, upper half of 

unit more resistant than lower half _______________ 5. 5 

2. Limestone, argillaceous, olive-gray (57 5/1) to greenish-gray 

(5GY 6/2), weathering light-olive-gray (57 7/1), to lightgreenish-gray (5GY '7/1), chiefly very fine grained, silty, 

probably clayey in part; small geoidal clusters, % to 1 in. 

across, of coarsely crystalline white calcite; a single set of 

rough beds % to 2% in. thick, many bedding planes discontinuous; forms small but prominent rough ledge. Sparse 

very fine and fine-grained fossil fragments of brachiopods 

bryozoans(?)______________________________ 1.5

Total Preachersville Member_______________________ 80

Rowland Member (incomplete) :

1. Mudstone, chiefly yellowish-gray (5Y 8/1), in places grayishyellowish-green (5GY 6-7/2) ; weathered rock is same colors 

or darker, approximately pale olive (10Y 6/1) ; slightly to 

very limy, silty; in even laminae and thin beds as much as 

2 in. thick; fissile, cleaving along smooth partings *4 to 

1 in, apart; nonresistant, forms slope; outcrop yields chips 

and small plates, a fraction of an inch to a few inches across, 

and irregular blocks commonly about % in. thick and 1 to 

3 in. long; no fossils seen. In part poorly exposed; about 

75 percent of interval is outcrop. Base of section is base of 

local exposure__________________________ 13

Measured Rowland Member (incomplete)_______________ 13

Measured Drakes Formation (incomplete)______________ 93
D36 CONTRIBUTIONS TO STRATIGRAPHY

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