BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 
VOL. 9, PP. 35-58 : JANUARY 18, 1898 
CLAY-VEINS VERTICALLY INTERSECTING COAL MEASURES 
BY W. 8S. GRESLEY 
(Presented before the Society August 10, 1897) 
CONTENTS 
Page 
alGrattste OCH Ce EHO MN eM eee a skcyceeysyo ake rapds czaeustousieysicsyetornereiecale ue aw eRe cok watch Seah al Wee estore, = 35 
We tina rorMoteanclayaVel Mein. alsieesciiesisec.-Gis Ryser sea dene ene ous Ae eee 36 
Some Peneral characteristics of clay-velns .......2--.2222 -22ch-0e+ seeeecee 36 
Wetalledideseription of a typicaleclay=veim...5. 22 sess. a2 essen ese eee dee 36 
IDIStiril NOM, Or CRN AVCIrlSam avins Gigs ae nee ain mignon mc SInete Gig oe Boer eae ates 38 
Vertical range....... ee ARG spor Se vetave a etal Stes a NU et grou SSE ins SER SS RS te 39 
HakOwaiumltyacOROneran Others. a... cic aerate fe shuclnd Sitio eee reteisc ds ayads Wareatvictous pels 40 
Faulting of clay-veins and its effects on the vein walls....................05. 41 
“ Horses” in the vein material....... ool ab tcbaliahstie Cooierevct en sk erate OEE were aoe te NE 42 
20 SVD PAIAS noel 6 Guess HSMN A CURT GIR ee ERE Me Ne aes Neel Ss eS ire Prin nn at ESL AUS 42 
SRUNCSHOING WOMANS AinNGl SUAS CHRRINCN Aelbpnonosaeas GancneuceseanocsH ae sccncde 43 
stn sere mee Niner iin Oe toeteen Varah ty alk ets ce deen cee aap ain atcove ie clement mere cua Wirceon yates a 43 
Fossiliferous variegated nodules in clay-veins.....................0-.00-- .. 44 
WitermcAatac tenis ticsyser.<seictcts a.4acel=) lees eee rle aeetes-e Dele & akon es See eS 45 
mOnricineormbexveimymaterials <2 5. s/c qejuaion tise sues ssealamenintns cs Sot geen 46 
“Slack-veins” or ‘‘soot-veins” in the Coal Measures of western Pennsylvania.. 47 
““ Horse-backs” in the Coal Measures of western Pennsylvania.......... Prose caS 
Age and origin of the CLA EVIEUNS! eso eee cera es bel rel ciara. veranatese Non Nee See en _ 48 
NC CMMOKOIonuOntlne slack-velMs). {= .- see oae aaa nee lene eee en ol 
MlLedapnenomenainvotherregions:.... seh amssssssaaeeetl ys asee ole 52 
INOWE: SCOURING a5 6 tor bomad REO iER Ian eae tod eA ion certain coer te wea 52 
TEMGHAIGLY a 3 Gta ASS 6 Sec eee One aM ae RE els eer eT sR Ba ON Va Rs pe 53 
INi@ty ZeallenGl SF ocockot rene ee caeen Ieee Re Resicimrerirne ecm rice ain rokr asc hs ares eam 55 
RON CES talte smear css yeh ccna vhs ote e oe a Ree in) aie 50 
CWomeludiMoNOWSERVALIOMSi a: leks okeiecclasleeies a. ors eau en nice Re omen se Sun os 56 
BULI@ereOINNG Tererres ONG eIsh-n > eeckg Sette eS DiisoN cso cr eao bo So acs sae See 57 
INTRODUCTION 
The purpose of this paper is to present a record of observations on 
dike-like deposits of clay and other material traversing the bituminous 
coal regions west of the Allegheny mountains, together with illustrations 
of and references to allied phenomena in other countries. 
VI—Butt. Gror. Soc. Am., Von. 9, 1897 (35) 
