8 NATURAL HISTORY OF SELBORNE. 



Cornua Ammonia are very common about this village. As we were 

 cutting an inclining path up the Hanger, the labourers found them 

 frequently on that steep, just under the soil, in the chalk, and of a 

 considerable size. In the lane above "Wall-head, in the way to Emshot, 

 they abound in the bank in a darkish sort of marl ; and are usually 

 very small and soft : but in Clay's Pond, a little farther on, at the end 

 of the pit, where the soil is dug out for manure, I have occasionally 

 observed them of large dimensions, perhaps fourteen or sixteen inches 

 in diameter. But as these did not consist of firm stone, but were 

 formed of a kind of terra lapidosa, or hardened clay, as soon as they 

 were exposed to the rains and frost they mouldered away. These 

 seemed as if they were a very recent production. In the chalk-pit, at 

 the north-west end of the Hanger, large nautili are sometimes observed. 



In the very thickest strata of our freestone, and at considerable 

 depths, well-diggers often find large scallops or pectines, having both 

 shells deeply striated, and ridged and furrowed alternately. They 

 are highly impregnated with, if not wholly composed of, the stone of 

 the quarry. 



LETTEE IY. 



TO THE SAME. 



As in a former letter the freestone of this place has been only 

 mentioned incidentally, I shall here become more particular. 



This stone is in great request for hearth-stones, and the beds of 

 ovens : and in lining of lime-kilns it turns to good account ; for the 

 workmen use sandy loam instead of mortar ; the sand of which fluxes,* 

 and runs by the intense heat, and so cases over the whole face of the 

 kiln with a strong vitrified coat-like glass, that it is well preserved 

 from injuries of weather, and endures thirty or forty years. When 

 chiseled smooth, it makes elegant fronts for houses, equal in colour and 

 grain to the Bath stone; and superior in one respect, that, when 

 seasoned, it does not scale. Decent chimney-pieces are worked from it 

 of much closer and finer grain than Portland ; and rooms are floored 

 with it ; but it proves rather too soft for this purpose. It is a freestone 

 cutting in all directions ; yet has something of a grain parallel with 

 the horizon, and therefore should not be surbedded, but laid in the 

 same position that it grows in the quarry.f On the ground abroad this 



of Selborne, refers it to the Ostrea carinata of Lamarck, a species peculiar to the 

 green-sand formation, upon which the village of Selborne is built, and which 

 from its white colour would be easily confounded with the chalk, especially at 

 a time when geology was much less attended to than at present. 



* There may probably be also in the chalk itself that is burnt for lime a 

 proportion of sand : for few chalks are so pure as to have none. 



t To surled stone is to set it edgewise, contrary to the posture it had in the 

 quarry, says Dr Plot, " Oxfordshire," p. 77. But surbedding does not succeed in 

 our dry walls ; neither do we use it so in ovens, though he says it is best for 

 Teynton stone. 



