310 proceedings of the academy of [1889. 



October 1. 

 Mr. Charles Morris in the chair. 

 Twenty-one persons present. 



Notes on the presence of Uvibral or Mountain Limestone in Lycoming 

 County, Penna. — The following communication from Mr. Abraham 

 Meyer, was read as part of the Proceedings of the Mineralogical and 

 Geological Section : — 



The" Umbral (Red Shale formation) No. XI of Prof. Rogers' 

 survey, divided by the State Survey into XIa, Xlb, XIc — the middle 

 member being called the Mountain Limestone — varies very much in 

 the southwestern portion of the State and in its further extension 

 through Virginia and Kentucky northward. It thins very rapidly 

 and is not identified in the late survey north of Huntingdon Co. 

 The formation Xlb claims our attention from the fact of its having 

 been altogether overlooked in the late survey of Lycoming County, 

 and from its importance as a horizon for the location of measures 

 occurring immediately above and below it. As it is in the south- 

 western portion of the State I have deemed the subject worthy of 

 interest. Formations of this character carry with them in their 

 widely distributed areas various deposits of commercial value, such 

 as iron ores and fire clays, which, because of the extent of their 

 exposure or outcrop, invite a very searching examination of their 

 importance. There seems to be the regular succession of measures 

 from No. XII — Serai Conglomerate, No. XIc, Umbral Upper Shale, 

 No. Xlb Umbral Limestone followedby No. XIa. 



The formation No. Xlb is shown in an exposure as a bold cliff on 

 Hogelan Run, 6 miles north of Cogan Station, N. C. R. R. On 

 the west side it is about 250 feet above the adjacent stream, about 

 1550 feet above ocean level at base of cliff, and about 1650 at the 

 top of the ledge. The cliff extends about 160 rods around the head 

 of a small run and then extends southwest a distance of about 2500 

 feet or more, the greatest vertical exposure being at the cliff locally 

 known as Kugler's Point, where it is about 50 to 60 feet in height, 

 forming a bold prominent cliff, an interesting feature in the land- 

 scape in passing up the gorge of Hogelan Run. Going over the 

 measures we find they can be divided into sections as in the 

 Trough Creek Valley deposits, as there seem to be various qualities 

 of limestone and associated rocks. There are some seventeen or more 

 changes of rock within sixty feet more or less — and among them we 

 can identify three or four limestone strata from two feet to fifteen feet 

 thick, some of which may have a value for agricultural purposes. 

 I have also found an outcrop of this same formation Xlb on Loy- 

 alsock Creek about A mile west of Barbour's Mills P. O. The meas- 

 ures there seem to thicken, especially XIc. Underlying the above 



