208 ME. JUKES-BROAVNE AND PROF. HARRISON 



The dwelling-house at Chimborazo stands on a small outlier of 

 coral-rock, the surface of which is just 1100 feet above the sea ; 

 another knoll to the north of this, and only a few feet less in elevation, 

 consists of dark red and yellow earths belonging to the argillaceous 

 group of the Oceanic Series (20 or 30 feet thick) resting on white 

 siliceo-calcareous earth, below which is purely- siliceous radiolarian 

 earth. 



The ridge connecting these knolls is traversed by a road, the 

 cutting for which shows the following beds : — 



feet. 



Whitish radiolarian earth, of small specific gravity , 5 



Bedded yellowish-white marl 4 



Hard brown marl, slightly gritty 0^ 



Firm yellowish marl, with patches of small brownish particles 1^ 



AH these beds contain radiolaria, and dip at 2° or 3" to the south- 

 east. 



The road on which this section is seen joins the main road that 

 runs northward down the slope of the escarpment, and the cuttings 

 for this show the middle and lower beds of the Oceanic Series down 

 to the very base, the total thickness, including the Chimborazo 

 section, being apparently about 250 feet. 



In the highest part of the road-cutting there is greyish gritty 

 earth, including a layer of bluish-grey sand about 5 feet thick, which 

 examination has shown to be mainly pumiceous. Below this is 

 whitish siliceous earth of small specific gravity, with some con- 

 centric ferruginous stainings and occasional pipings of a buff- 

 coloured material ; these beds include a thin layer of grey marl. 

 The road then crosses a combe and passes by cottages where 

 no section is visible, probably hiding the Castle Grant gritty beds. 

 Opposite the Schoolhouse a cutting in the lower spur of the hill shows 

 whitish and somewhat calcareous earth ; just below this, where a road 

 branches off, the basal beds,white5 chalky, and heavy, are seen resting 

 on dark sandy clay. This place is known as Melvin's Hill. 



Canefield and Forey's Spring. — On the Canefield estate the basal 

 beds are very chalky, containing 83 per cent, of calcium carbonate ; 

 they are quarried and are used by the coopers on this and other 

 estates instead of imported English chalk. The higher slopes 

 consist of siliceous earths, and the highest ridge on the neighbouring 

 estate of Highland is capped by a mass of chocolate-red argillaceous 

 earth. The Oceanic Deposits are exposed along the floor of the deep 

 gully which cuts through the escarpment of the coral-rock between 

 Canefield and Mount Misery, and can be seen at intervals as far as 

 Percy's Spring, a distance of about a mile. Their continuity, how- 

 ever, appears to be broken by faults ; the basal chalky beds are 

 exposed by the side of a cross-road about a quarter of a mile from 

 the top of the gully, but a little farther there is siliceous earth 

 dipping to the N.N.W. 



In the main road south of Percy's Spring there is white siliceous 

 earth dipping to the N.N.W. at 4° or 5°, covered by coral-rock, and 



