the llwellyn formation occupies all of the northern and central reaches of the south branch newport creek watershed. south of the llwellyn formation is the pottsville formation. south of the pottsville formation is the mauch chunk formation and then the pocono formation. the southernmost reaches of the watershed are occupied by rock of the duncannon member formation. the area near the mouth of the creek, it flows over a coal sheet called sheet iii. south of the middle reaches of the tributary reservoir creek, all of the soil belongs to the lackawanna-arnot-morris series. north of this area, the soil all belongs to the udorthents-urban land-volusia series.