—_— 
Mauch Chunk of Pennsylvania.—Stevenson. 247 
Seminula or Dielasma are shown on weathered surface but 
all are very imperfect and none can be detected in tne 
eS OEY sate Soin acs tir a ERE TN Fe yk vege veka cans a 4 
24. Not fully exposed, but mostly brown shale.................. 12’ 
25. Limestone, impure with fragments of crinoid stems, and 
enesll: Seinitete all crime vals nae one Ss aeons. 0 10" 
ae UIIONY SOOMDERIOG: Ail dda vieiibs ire ceili brele SOi8 b Wk Belem sb2 a2 one s 
27. Sandstone or leached afenaceous limestone,............... V 
MIG, BORO, © Cos by et unh und vb sab cGy sve s ye Ane Ree 12’ 
NORM... Sota thp ca CR tae eae eo bade rN Cee bY va neees » 2 
30. The Silicious limestone. This is not reached on the slope, 
but one can follow Nos. 28 and 29 westward for 200 feet 
to a deep ravine which opens behind the Snyder house, 
where the limestone is exposed for fully 200 feet. The 
rock, known as “whinstone,” was quarried here in immense 
quantities for use on the National road, being preferred to 
the less resistant rock from the other quarry. The peculiar 
current-bedding characterizing this rock everywhere, 1s es- 
pecially notable in the lower portion, the bedding becoming 
comparatively regular in the top seven feet. The general 
structure resembles that seen in the consolidated dune sands 
Ree RESORT ICES R. (wes viics Oia Trehanee's Atte cu siete ta, d < Caos Pete 35 
. 
TEORRY TECRMOBS @OOTORUITACELY oo sic es Gees estes cee eegad 250 feet. 
The dip is southeastward at 14 or 15 degrees. The dips 
in this Chestnut (Laurel) hill are frequently very steep, 
being considerably more than forty degrees at one locality 
on the western flank, and, generally speaking, steeper than 
those of Laurel hill and other axes to the eastern edge of 
the Allegheny plateau in southern Pennsylvania. 
Mr. Meek, in 1870, decided that the fossiliferous lime- 
stone is of Chester age. By means of the more extensive 
collection, Dr. Weller has been enabled to make a closer ap- 
proximation to the horizon. He finds the fauna ‘essentially 
identical with that of the Maxville limestone in Ohio” as de- 
scribed by R. P. Whitfield in Vol. VII of the Ohio reports, 
so that he thinks “it will probably be safe to correlate the 
formation with that limestone.” This conclusion is in ex 
act accordance with the stratigraphical relations, for this 
upper limestone is continuous with the Maxville. 
Respecting its relations to the rocks of the Mississippi 
valley, Dr. Weller’s conclusions differ very slightly from 
those of Mr. Meek, who recognized the fauna unhesitatingly 
as Chester. Dr. Weller writes respecting the Maxville and 
Fayette county faunas that “they are of Genevieve age—a name 
, 
