68 THE CAMBRIAN AND ORDOVICIAN DEPOSITS OF MARYLAND 



Middle Cambrian red beds for which the term Waynesboro was proposed, 

 is different from the Wautaga facies to the south in that considerable 

 thicknesses of sandstone and limestone are intercalated with the char- 

 acteristic-red and purple shales. Moreover, there are two other names 

 whose claims must be considered before this nomenclatural question can 

 be finally settled. These names are the Eome sandstone and shale and 

 Eussell shale, both in good standing and of prior dates than Wautaga 

 shale. Provisionally, therefore, it is thought advisable to retain the name 

 Waynesboro formation for these strata in Maryland and Pennsylvania. 



LITHOLOGIC CHARACTER AND THICKNESS. In Maryland as well as in 

 the type area of outcrop, the Waynesboro formation consists of a lower 

 member of very siliceous gray limestone and calcareous sandstone, a 

 middle member of limestone, and an upper one of red and purple siliceous 

 shale, aggregating 1000 feet in thickness. Of the three members, the 

 upper is the best developed and most frequently exposed, since faulting 

 often cuts out the middle limestone and lower sandstone divisions. The 

 weathering of this upper part is mainly responsible for the characteristic- 

 red color of the soils derived from the formation. The basal siliceous 

 limestones weather into shaly, porous sandstone with which are associated 

 numerous blocks of secondary white vein quartz and rounded corrugated 

 sandy fragments full of crevices lined with small quartz crystals. The 

 limestones of the middle division range from dark blue massive limestone 

 to fine grained white marble which, on account of their soluble nature, 

 are generally not exposed. In Pennsylvania this middle portion is several 

 hundred feet thick, but in Maryland the thickness is probably not as 

 great. These limestones become siliceous toward the top of the member 

 and finally seem to grade into the dark red to purple sandy shale which 

 makes the upper part of the formation. Certain parts of the upper mem- 

 ber contain argillaceous flaggy sandstone which has been locally quarried 

 for paving stones. On weathered surfaces the flags break up into frag- 

 ments of sandy shale. 



Such slabs frequently exhibit ripple marks and mud cracks, the latter 

 being well displayed in some of the paving stones of Smithsburg. One 



