FROSTBTTRG COAT. FORMATION. 97 



The whole series rests unconformably on the old red sand- 

 stone, which appears on tlie western side of Savage mountain, 

 about 1400 feet from the summit, as represented in the 

 sections in plate 2. It dips at an angle of about 20° under the 

 coal rocks, and re-appears on the eastern flank of Dan's moun- 

 tain, with a western dip. When first seen in the gap of Jen- 

 ning's run, its inclination is also about 20°, but the strata 

 curve upwards at a greater distance from the axis of the 

 mountain, and become much more highly inclined. Among 

 the fossils in the red sandstone, which are all marine, only 

 the Producti were determined. Towards the western base of 

 Dan's mountain, the sandstone alternates with red limestone, 

 and finally gives place to the carboniferous, or mountain lime- 

 stone, against which it rests conformably. Producti have also 

 been met with in this limestone. In colour, it varies from 

 brown to dark blue, and is cavernous: it is inclined at a high 

 angle, and rests conformably upon the siliceous white sand- 

 stone of Wills' mountain. The structure of this mountain, 

 is well exhibited at the gap traversed by the waters of Wills' 

 creek; an escarpment on the northern side, reaches an eleva- 

 tion of about 900 feet above the creek, and on the western 

 portion, is covered by a talus for several hundred feet from its 

 base. The central portion of the mountain consists of old 

 red sandstone, which like that under the coal series, is made 

 up of alternations of moderately hard sandstone, and a softer 

 variety passing into shale. When first seen on its western 

 limits, it is highly inclined, and dips westwardly. The strata 

 then bend over in the form of a flattened arch, and dip to the 

 eastward, with an inclination of 12° or 15°, until they 

 pass under the bed of tlie creek. It is covered by beds of the 

 siliceous sandstone, before referred to, which are several hun- 

 dred feet in thickness, and form the summit and flanks of 

 Wills' mountain; on the western side, they are almost ver- 

 tical, and then curving to the eastward, are nearly horizontal 

 at the summit; on the eastern side, we find them bending 

 down until they dip about the same as the red sandstone upon 

 which it rests. At the base of the mountain, the limestone 

 precisely similar to that which was mentioned on the western 

 side, rests conformably upon this siliceous sandstone, and is 



13 



