BY H. I. JENSEN. 



885 



Dip 

 S.E. 



at 

 25^^ 



With Permo-Carbo- 

 niferous fossils. 



strata observed from the bottom of the cliff to the top is seen in 

 the following statement : — 



/ Top of hill — Trachyte under which we have conglomerate, thick- 

 / ness not estimated. 



Top of cliff —The same conglomerate. 

 Then — Sandstone, 30 feet. 



Cherty Mudstones, 20 feet. 

 Felspar Porphyry Sill (Bostonite), 6 feet. 

 Cherty Mudstone, 9 feet' 

 Soft Blue Shales, 6 feet 

 Cherty Shales, 4 feet 

 ,, „ 7 feet 



Black Shale, 6 inches 

 Bottom of / Sill with black phenocrysts and fragments, 2ft 9in., 

 Cliff, J then Sandstone, 3 feet. 

 Dingo I White Shales, 1 foot. 



\ Creek, y Cherty Mudietones, thickness unknown. 



Level of Creek, 



Microscopic examination : texture holocrystalline, extremely 

 uneven-grained on account of the monstrous phenocrysts set in 

 the microcrystalline base. The base is quite aphanitic, but with 

 a ;^-inch objective it is resolved and appears to be holocrystalline 

 with a camptonitic fabric. 



Composition : the crystal aggregates or fragments are seen 

 under the microscope to have a more broken outline than the 

 handspecimen shows. They consist of olivine, light greenish 

 diopside, enstatite and colourless augite in hypidiomorphic to 

 allotriomorphic crystals, the whole aggregate having a hypidio- 

 morphic granular texture. Between the crystals are strands of 

 a white fibrous chloritic decomposition-product, apparently 

 margarite. Fragments of picotite are also present. The black 

 phenocrysts are somewhat corroded along the margin, having a 

 resorption rim resembling the celyphitic border of garnet. They 

 consist of a species of hypersthene or amblystegite. The mineral 

 has three well marked cleavages, two of which are at right 

 angles; there are also two pinacoidal partings to which extinc- 

 tion is parallel. The pleochroism is weak, and the double refrac- 

 tion is also weak, being about the same as that of labradorite. 



