210 Geological and Mhieralogical Survey 



A stratum of limestone, but too much contaminated with iron 

 to be used for agricultural purposes, crops out on the east side of 

 Cold moor. It is about eight or ten feet thick: and in the trans- 

 verse veins are observed stalactites, curiously formed, some of 

 them studded with pyramidal crystals of calc spar, commonly 

 called dog's tooth spar. 



In the front of some of the Cleveland hills, where the beds of 

 indurated clav crop out, are seams of a fine yellow ochie, similar 

 to the Oxford stone ochre. The same hills contain, in the bitu- 

 minous shale, balls of a rich yellowish brown ochre, perfectly free 

 from grittiness; perhaps produced by decomposed pyrites. — In 

 the upper end of Greenhoue Burton, is a rock called the Rudd 

 scar^ from a seam of ruddle, or red ochre, which it contains, with 

 which the farmers mark their sheep. 



The sandstone beds which lie above the aluminous schistus are 

 all siliceous; but differ greatly in their texture and hardness, 

 some being soft and friable, while others are well adapted for 

 building. On the tops of some of the moors a very hard siliceous 

 stone, called crow stone, occurs. Near Hunt-house, in Godeland, 

 is a large bed of stone, composed of fine white crystals, having 

 so little cohesion, that the stone is easily crumbled to pieces be- 

 tween the fingers: the powder is used by farmers for sharpening 

 their scythes. — Most of the sandstone contains mica; which oc- 

 curs in a schistose state between the strata of sandstone, and is 

 also found in fissures, in loose scales, vvhich from their bright lustre 

 have been sometimes taken for metallic ores. 



Such is the stratification of the first three ranges of hills, 

 which we may call the alum hills. In the southern slope of the 

 third line, the aluminous bed sinks below the level of the sea, 

 and rises no more. Its descent is rather rapid; for though it ap- 

 pears at a great height at Stoupe Brow, it sinks about a mile to 

 the south of Peak; and the descent takes place in a similar form, 

 throughout the whole of this range of hills, from Peak to Osmo- 

 therley, the place where it disappears on the Cleveland side. The 

 •uperincumbent strata sink at a proportionate distance to the 

 south, and then commences a new series of stratification, com- 

 posing the fourth, or southern, line of hills. These we may term 

 the limestone hills, as they consist of alternate strata of limestone, 

 marl, and sandstone, resting on a bed of clay slate, of a coarse 

 granular texture, and a light gray colour. This slate lies over 

 the upper strata of the former series, that sinks beneath this ; 

 for this series has the same inclination as the former, dipping gra- 

 dually towards the south, till it sinks in the vale of Pickering, or 

 of the Derwent; beyond which another series appears ia the 

 chalky strata of the wolds. 



The limestone is chiefly of the oolite or roe-stone species; and 



contains 



